cell counts pt 1
How many large hemacytometer squares contain a total volume of 1 µL (microliter) of fluid? The correct answer is highlighted below 5 10 15 18
Volume = area x depth Each square has an area of 1 mm2. Chamber depth = 0.1 Volume = # of squares counted x 0.1µL (chamber depth) # of squares counted = volume/0.1 or volume x 10 If the volume is 1, the number of squares counted is 10.
Normal adult CSF may have 0-5 white blood cells (WBCs)/µL. Which of the following cell types account for 60-100% of these WBCs? The correct answer is highlighted below Neutrophils Lymphocytes Monocytes Eosinophils
Typically, majority of cells seen in a normal adult CSF specimen are lymphocytes and monocytes (70:30 ratio). This ratio is reversed in children.
A dilution commonly used for a routine sperm count is: The correct answer is highlighted below 1:2 1:20 1:200 1:400
A manual sperm count is performed in the laboratory by using a Neubauer counting chamber. A dilution commonly used for the routine sperm count is a 1:20 dilution. The diluent is usually made of sodium bicarbonate and formalin which immobilize and preserve the sperm cells for the count.
Blood is diluted at 1:100 and charged on the hemocytometer counting chambers on both sides. If the average platelet count from a counting chamber in one mm2 (one large square) is 68, what is the calculated platelet count? The correct answer is highlighted below 680,000/mm3 6,800/mm3 68,000/mm3 34,000/mm3
A simple way to calculate platelet counts on the hemocytometer is to multiply the average platelet count between the two sides of the chamber by 1,000. In this case 68 x 1,000 = 68,000 platelets. The longer derivation is as follows: The standard dilution of blood for platelet counts is 1:100; therefore the dilution factor is 100. The volume of diluted blood used is based on the area and depth of the counting area. The area counted is 1 mm2 per side (since we are using the average platelet count, we only use the area of one side) and the depth factor is 10. ((Total number of cells counted x dilution factor x depth factor(mm)) / area in mm2) = platelets per mm3 Note: 103/mm3 = 103/µL = 109/L
Which of the following is the recommended method for preparing a cerebrospinal fluid (CSF) sample for a differential count? The correct answer is highlighted below Cytocentrifugation The concentration of cells by traditional centrifugation Manual smear methods Use of hemocytometer
A slide for microscopic examination of CSF should be made using a cytocentrifugation technique (cytospin). Alternate methods of slide preparation, such as concentration of cells by traditional centrifugation, manual smear methods, and counting chambers are not recommended as morphologies may not be maintained and sufficient cells may not be present on the slide for the accurate evaluation of the sample.
What is the optimal time to begin initial microscopic examination of a semen specimen, assuming liquefaction is complete? The correct answer is highlighted below 30 minutes 2 hours 4 hours 8 hours
According to the 5th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, the analysis should begin at 30 minutes (if liquefaction is complete), but no longer than one hour after ejaculation. Occasionally a specimen does not liquefy. If this occurs, mechanical mixing or enzyme treatment may be necessary in order for the sperm count, motility analysis and other microscopic aspects of semen analysis to be performed.
A 1:10 dilution is made on a CSF sample. Five squares on each side of the hemacytometer are counted for a total of 10 squares and a total of 150 cells are recorded. What is the count per microliter? The correct answer is highlighted below 527 758 833 1500
According to the formula on the right, here is how we arrive a the 1500 cells per microliter: Cells/µL = 150 x 10/ 10 x 0.1 µL Cells/µL = 1500 / 1 = 1500/µL
A manual white blood cell count was performed by the hematology technologist. The cell counts for each of two sides was 38 and 42 respectively. All nine large squares were counted on each side. The dilution for this kit was pre-measured at 1:10. What should the technologist report as the white cell count? The correct answer is highlighted below 4.8 x 109/L 4.4 x 109/L 0.48 x 109/L 0.44 x 109/L
Calculation: Cells Counted (in this case the average of both sides) X dilution factor (in this case 10) / # of sqaures counted (in this case 9) X 0.1mm (depth of solution) X area of each square (1mm2) So, in this problem: (40 x 10) / (9 x 1mm2 x 0.1mm) = 444.4/mm3 (can be converted to 0.44 x 109/L)
A cell count is ordered on a CSF sample that is bloody. Which of the following procedures would improve the non-nucleated cell count accuracy? The correct answer is highlighted below Dilute the sample to minimize the number of red blood cells in the squares being counted. Use Spinal Diluting Fluid, a mixture of acetic acid and crystal violet. Use an automated hematology cell counter. Use of electronic cell counter.
Dilute the sample to minimize the number of red blood cells in the squares being counted. A total cell count could be performed initially by using saline, mixed by inversion, and loaded into the hemocytometer. If the sample were diluted with a mixture of acetic acid and crystal violet to minimize the number of RBCs, a more limited number of WBCs may not be visible in the counting area. This method is not recommended. Automated hematology cell counters usually do not have the low-end sensitivity needed to accurately count CSF samples. The use of electronic cell counters is not the normal practice for counting CSF cells due to high background counts and poor reproducibility of a low count.
Which of the following ranges is the reference range for hematocrit for an adult male? The correct answer is highlighted below 14 - 18 g/dL 12 -16 g/dL 35 - 47% 40 - 52%
Feedback The reference range for hematocrit for an adult male is 40 to 52 %. 14 - 18 g/dL represents the reference range for hemoglobin on an adult male. 12 - 16 g/dL represents the reference range for hemoglobin for an adult female. 35 - 47% represents the reference range for hematocrit for an adult female.
A manual WBC count was performed. A TOTAL of 72 cells were counted in 4 large mm squares of a Neubauer-ruled hemacytometer. A 1:20 dilution was used. What is the calculated WBC count? The correct answer is highlighted below 0.4 x 103/µL 1.8 x 103/µL 3.6 x 103/µL 4.0 x 103/µL
First, determine the number of WBC's from the hemacytometer as follows: WBC count = (dilution ratio x # of cells counted x 10) / (# mm2 area counted) Then: WBC count = (20 x 72 x 10) / (4) = 3600 WBC/µL (or 3.6 x 103 WBC/µL)
A WBC differential count on CSF should be performed using the following technique: The correct answer is highlighted below Wet mount of sample from collection tube Stained smear of a cytocentrifuged specimen Directly from hemocytometer chamber count Directly from stained hemocytometer count
They make and/or stain the bone marrow smear. The MLS or laboratory technologist's role may include making smears, either at the patient bedside or in the laboratory and staining the smears. They do not prepare the patient, perform the procedure, or interpret the results. Typically a nurse prepares the patient for the procedure. The clinician or pathologist obtains the bone marrow samples, which include aspirates or biopsies. The pathologist then examines and interprets the bone marrow smear.
Cell counts on CSF specimens should be performed within what time frame following collection of the CSF sample? The correct answer is highlighted below Within one hour Within four hours Within eight hours Within 24 hours
Within one hour CSF cell counts should be performed within one hour of sample collection. Both red blood cells (RBCs) and white blood cells (WBCs) have limited stability in CSF because CSF is hypotonic, and cells can rapidly lyse. Timing is especially critical for WBCs since both the number and type of cells present are clinically important in diagnosing cases of meningitis and detecting CNS leukemic involvement.
A semen sample for semen analysis should generally be received at the testing site within what period of time? The correct answer is highlighted below One hourTwo hoursThree hoursFour hours
It is recommended that a semen analysis sample be delivered within one hour to ensure accurate testing results. The semen specimen is examined under a microscope to determine the concentration, motility (movement), and morphology (appearance and shape) of the sperm. Since it is important to observe the sperm while they are still active, samples must be received for analysis within an hour.
Charcot-Leyden crystals in stool may be associated with an immune response and are thought to be the breakdown products of: The correct answer is highlighted below Neutrophils Eosinophils Monocytes Lymphocytes
Charcot-Leyden crystals in stool are thought to be created from damaged eosinophil byproducts. These crystals have a strong association, although they are rare, with parasitic infections or allergic reactions.
What is the corrected white blood cell count if the WBC is 14,460, and there were 47 nucleated red blood cells per 100 white blood cells noted on the differential count? The correct answer is highlighted below 6,796 9,837 10,165 21,256
Corrected WBC count = uncorrected WBC count x (100 / NRBCs +100) Corrected WBC count = 14,460 x (100/147) = 9,837
Platelet satellitism is most likely to cause which of the following erroneous results? The correct answer is highlighted below Falsely increased WBC count Falsely decreased RBC count Falsely decreased platelet count Falsely decreased hemoglobin level
Platelet satellitism, platelets sticking to the periphery of neutrophils, would cause a falsely decreased platelet count. This is caused by EDTA.
What should be added to the cytocentrifuge chamber when preparing slides on serous fluids to aid in the adhesion of cells to the slide and preserve cellular morphology? The correct answer is highlighted below Hyaluronidase 22% Albumin 10% acetic acid Sterile saline
10-22% Albumin should be added when preparing serous fluids and CSF. The addition of albumin helps preserve cellular morphology and improves adhesion to the slide. Hyaluronidase can be added to synovial fluids to help overcome the increased viscosity of these fluids during slide preparation. 10% acetic acid can be used as a diluent for grossly bloody serous fluids and CSF. The acetic acid lyses the red blood cells to increase the visualization of the nucleated cells present. Sterile saline can be used to make dilutions of fluids with red blood cell counts less than 5000 cells/mL. This saline dilution also assists with the visualization of the nucleated cells present.
A manual white blood cell count was performed by the hematology technologist. The cell counts for both sides were 152 and 164 respectively. All nine large squares were counted on each side. The dilution for this kit was pre-measured at 1:100. What should the technologist report as the white cell count? The correct answer is highlighted below 177.5 x 109/L 17.5 x 109/L 1.75 x 109/L 175 x 109/L
17.5 x 109/L Calculation: Cells Counted (in this case the average of both sides) X dilution factor (in this case 100) / # of squares counted (in this case 9) X area of each square (1 mm2) X 0.1 mm (depth factor) So, in this problem: 158 x 100 / 9 x 1 x 0.1 mm = 17555.55/mm3 (can be converted to 17.5 x 109/L*) *There are 1,000,000 mm3 in a liter (L). So 17555.55 X 1,000,000 = 17.5 x 109/L
Which of the following laboratory test results indicates that a sickle cell patient may be in aplastic crisis? The correct answer is highlighted below Decreased reticulocyte count Decreased haptoglobin level Increased bilirubin level Increased lactate dehydrogenase (LDH)
A decreased reticulocyte count may indicate a halt in the production of red blood cells. Aplastic episodes in patients with sickle cell disease are often associated with infection, particularly parvovirus infection. Decreased haptoglobin, increased bilirubin, and increased LDH are all consistent with hemolysis and not an aplastic condition.
Which of the following bone marrow sampling methods would be advisable if the quantity is inadequate for an aspirate smear? The correct answer is highlighted below Touch imprintBone marrow core biopsyDirect aspirate smearClot section
A touch imprint can be performed if the bone marrow sample is insufficient. Cytomorphology and M:E ratio can be determined by this sampling method. The bone marrow core biopsy, which is especially recommended for dry taps, the aspirate, and the clot section, all require a more significant amount of bone marrow.
An increased reticulocyte count MAY be found in all of the following conditions, EXCEPT? The correct answer is highlighted below Hemolytic anemias Following acute hemorrhage Aplastic anemia Satisfactory response to therapy for pernicious anemia
Aplastic anemia does not cause the bone marrow to release immature red blood cells because it is a pluripotential stem cell disorder that leads to peripheral blood pancytopenia and hypoplastic marrow. Hemolytic anemias, active blood loss, and successful treatment of pernicious anemia all cause an increase in reticulocytes in the peripheral blood, as the bone marrow attempts to replenish the decreased quantity of peripheral RBCs.
A 3-year old girl was brought to the ER with a temperature of 103ºF, lethargy, and cervical rigidity. Three tubes of cloudy CSF were delivered to the Lab, and preliminary test results showed: WBC: 4,500/µL Differential: 88% neutrophils Glucose: 15 mg/dL 12% lymphocytes Protein: 140 mg/dL Gram stain: No organisms observed From these results, what preliminary diagnosis SHOULD the physician consider? The correct answer is highlighted below Brain tumor Bacterial meningitis Viral meningitis Subdural hematoma
Due to the elevated white blood cell count along with a strong percentage of neutrophils, a bacterial infection should be suspected. Though there are no organisms seen on the gram stain, a bacterial infection is still very possible as the bacterial count in the spinal fluid may be low. A viral meningitis would be more closely associated with an increased quantity of lymphocytes. Brain tumors and subdural hematomas would not be associated with these laboratory findings.
During capillary collection from a young child, which of the following lab results may be falsely increased due to excessive crying? The correct answer is highlighted below Hemoglobin Hematocrit White blood cell count Red blood cell count
During the collection of capillary blood from an infant or a young child, stress can play a negative effect on the test results. Excessive crying in infants can increase the white blood cell (WBC) counts. Stress can cause WBC's from the marginating pool (those by the wall of the vessel) can detach and enter the circulating pool (those floating through the vessel). It takes at least 60 minutes for the WBC levels to return to normal. If an infant has undergone a painful procedure, care must be taken to allow the proper time to pass before collecting capillary blood. Hemoglobin, hematocrit, and red blood cell count are not affected by stress such as excessive crying.
A 90-year-old patient is admitted to the hospital with the following laboratory data: WBC: 9,000/mm3 PLT: 190,000/mm3 Hgb: 6.1 g/dL Differential: 11% Neutrophils 40% Lymphocytes 4% Monocytes 45% Myeloblasts 45 NRBC's / 100 WBC Bone Marrow: 45% Myeloblasts & 55% Megaloblastoid Erythroblasts Serum Vitamin B12 and Folic Acid: Normal The MOST likely diagnosis is: The MOST likely diagnosis is: The correct answer is highlighted below Pernicious anemia Polycythemia vera Erythroleukemia Myelomonocytic leukemia
Erythroleukemia is also known as Acute Myelogenous Leukemia type M6. This type is associated with either the presence of both erythroid and myeloid precursors OR strictly erythroid precursors. In the case above, there are both erythroid and myeloid precursors present in the peripheral smear. Pernicious anemia would have shown an abnormal serum vitamin B12 level and would not have been associated with the myeloid precursors or the large amount of erythroid precursors demonstrated in this case. Polycythemia vera is associated with very high levels of red cells, white cells, and platelets, which is not found in this case. Finally, myelomonocytic leukemia is associated with an increase in myeloid and monocytic cell precursors, but not red blood cell precursors.
A technologist performed a STAT spinal fluid count by pipetting undiluted spinal fluid in a Neubauer Counting Chamber and counting both sides of the chamber (4 large WBC squares on each side). A total of 54 White Cells were counted. How many White Cells would there be per cubic millimeter? 3.80 67.5 13.5 300
First, determine the number of WBC's from the hemacytometer as follows: WBC/µL= Avg # cells counted /(# squares counted x 0.1 µL) WBC = 54 / (8 squares x 0.1 µL) = 67.5/µL Since 1 µL = 1 cubic millimeter, then the answer is 67.5/µL. *Note in this question, both sides were counted without separate values given for the average to be obtained; therefore, substitute the total cell count in the numerator with the total squares counted in the denominator. Also, there was no dilution for the specimen, so the dilution factor will not be included in the equation.
A 1:20 dilution is made for a manual WBC count. The four corner squares on both sides of a hemocytometer are counted. A TOTAL of 100 cells are counted (eight total squares). What is the white blood cell count in terms of a liter? The correct answer is highlighted below 2.5 x 109/L 25 x 109/L 2,500/L 25,000/L
First, determine the number of WBC's from the hemocytometer as follows: WBC count = (dilution ratio x # of cells counted x 10) / (# mm2 area counted) Then: WBC count = (20 x 100 x 10) / (8) = 2500 WBC/mm3 (or 2500 WBC/µL or 2.5 x 103 WBC/µL) To find the WBC count per liter, multiply the WBC count/µL by the number of µL/L (there are 106 µL/L) So: (2.5 x 103 WBC/µL) x (106 µL/L) = 2.5 x 109 WBC/L
Which of the following analytes will be falsely decreased due to hemolysis? The correct answer is highlighted below Potassium, Magnesium, Hemoglobin Potassium, Magnesium, Iron, Total Protein Hematocrit, Red Blood Cell Count, Potassium Hemoglobin, Hematocrit, Red Blood Cell Count
Hemoglobin, Hematocrit, Red Blood Cell Count Extreme care should be taken in order to avoid hemolysis of the specimen. When the specimen is hemolyzed, the concentration of analytes is changed, and the results are inaccurate. Falsely increased results include potassium, magnesium, iron, lactate dehydrogenase, phosphorus, ammonia, and total protein. Some of the results falsely decreased include red blood cell count, hemoglobin, and hematocrit.
What is a corrective action that can be used to obtain a valid platelet count from a patient specimen that exhibits platelet satellitism on the manual differential? The correct answer is highlighted below Redraw the patient specimen in another EDTA collection tube and wait 20 minutes before sampling. Refrigerate the patient sample for 30 minutes prior to sampling. Invert the EDTA tube several times prior to sampling. Recollect the blood specimen in a blue top tube containing sodium citrate.
If platelet satellitism is observed on the peripheral smear, the sample should be recollected using sodium citrate as the anticoagulant. Platelets can then be counted using the automated method. The platelet count from a tube that contains liquid sodium citrate will need to be corrected for the dilutional effect of the citrate; this can be accomplished by multiplying the platelet count that is obtained from the automated analyzer by 1.1. Any suggested remedy that involves the use of EDTA as the anticoagulant will not be effective because the presence of EDTA is causing the satellitism to occur.
For which determination is the brilliant cresyl blue stain used MOST often? The correct answer is highlighted below Malaria - ring forms Plasma Cells Reticulocytes Basophilic stippling
Immature erythrocytes, or reticulocytes, contain nuclear remnants of RNA. To detect the presence of this RNA, the red cells must be stained while they are still living, in a process called supravital staining. With supravital staining, the RNA appears as a reticulum within the red cell. Brilliant cresyl blue and new methylene blue are examples of supravital stains. Malaria ring forms and plasma cells can be visualized with Wright's stain. Supravital staining is not necessary for these cells. Basophilic stippling granules are composed of ribosomes and RNA. Due to the RNA content, cells with basophilic stippling can be seen with supravital staining. However, cells with basophilic stippling can also be visualized on Wright's stain.
Classic automated blood cell counters are based on which of the following technologies? The correct answer is highlighted below Laser scatter Radiofrequency Unifluidics Impedance principle
Impedance principle The Coulter or impedance principle became the industry standard in the early 1960s. It is still considered one of the basic principles of cell counting automation regardless of the sophistication of the instrument. Radiofrequency is a modification of the impedance principle. Laser scatter is typically used in conjunction with other methods and is employed in later generations of hematology instruments. Unifluidics technology is a newer methodology incorporated into instrumentation provided by Siemens.
How many white blood cells (WBCs) would be considered normal for adult cerebrospinal fluid? The correct answer is highlighted below Any number of WBCs is considered abnormal 0-5 WBCs/µL 6-10 WBCs/µL Up to 30 WBCs/µL
In an adult, 0 - 5 WBC/µL is considered normal. Children will have slightly higher cell counts. Up to 30 WBC/µL is within normal limits for newborns. Lymphocytes account for 60 - 100% of these cells.
A sample of cerebrospinal fluid is diluted 1:100; the standard 9 squares of a hemocytometer were counted on each side for a total of 18 large squares. Side 1- 186 cells counted Side 2- 184 cells counted total cells = 370 What is the cell count per microliter? The correct answer is highlighted below 1.03 x 104 2.06 x 104 4.62 x 104 9.25 x 104
In this example, we would use the standard manual WBC count equation. Cells/µL = # of cells counted x dilution / # of large squares counted x 0.1µL (chamber depth) In this case, Cells/µL = 370 x 100 / 18 x 0.1 Cells/µL = 37000 / 1.8 Cells/µL = 20556 or 2.06 x 104
Which of the following cells would be increased if the cerebrospinal fluid (CSF) of a patient suspected of having multiple sclerosis? The correct answer is highlighted below Neutrophils Lymphocytes Macrophages Monocytes
Increased lymphocytes are typically associated with viral infections. There are also noninfectious causes for increased lymphocytes, such as multiple sclerosis. Infectious causes for increased lymphocytes include viral meningoencephalitis, aseptic meningitis syndrome, fungal meningitis, and syphilitic meningoencephalitis. Neutrophils in the CSF are indicative of a bacterial infection. Several infectious disorders result in an increase in neutrophils, such as untreated bacterial meningitis, viral meningoencephalitis, early tuberculosis, and mycotic meningitis. Macrophages can be seen in cases of meningitis or meningeal inflammation, infectious diseases, CNS leukemia, lymphoma, and malignant melanoma. Increased monocytes can be seen in tuberculous meningitis, syphilis, subarachnoid hemorrhage, and viral encephalitis.
A two-year old male patient has the following hemogram results: Hgb = 6.7g/dL Hct = 20% Platelets = 355 x 109/L RBC = 3.0 x1012/L WBC = 8.75 x 109/L Differential = 6% eos, 20% segs, 68% lymphs, 6% monos Which of the following is the MOST likely diagnosis? The correct answer is highlighted below Dietary iron deficiency Idiopathic thrombocytopenia Lymphocytic leukemia Lead poisoning
Iron deficiency anemia is the most likely diagnosis because the RBC, Hct, and Hgb are all very low. Idiopathic thrombocytopenia can be ruled out since the platelet count is normal.Lymphocytic leukemia can also be ruled out because the WBC is normal.Finally, lead poisoning is ruled out since this condition does not usually cause severe anemia.
What would be the logical first step to obtain correct values when the following results were obtained on an electronic particle counter in hematology for an alcoholic patient? WBC 6,500/cu. mm MCV 90.1 fL RBC 4,550,000/cu. mm MCH 39.6 pg HGB 18.0 g/dL MCHC 43.4% HCT 41.5% The correct answer is highlighted below Perform a microhematocrit Check and correct for lipemia Dilute the blood Replace the lysing agent
Lipemia can cause increased hemoglobin results on automated hematology analyzers since the hemoglobin measurement is performed spectrophotometrically. The lipemia in the sample causes a more turbid sample, leading to a falsely high reading during the hemoglobin determination. Since the hematocrit is a calculated parameter on automated hematology analyzers, it would not be necessary to perform a spun microhematocrit. The parameters used in the calculation would not be affected by the presence of lipemia. To troubleshoot a falsely increased hemoglobin due to lipemia, one could perform a saline replacement. This procedure replaces lipemic plasma with saline in order to resolve the discrepancy. A simple dilution would not correct the issue with turbidity due to lipemia. The lysing reagent is used to break apart the red blood cells in order to get an accurate hemoglobin reading. If the lysing reagent were not working properly, you would see a decreased hemoglobin, not increased as in the question.
All of the following methods are used to detect and differentiate white blood cells in most hematology analyzers, EXCEPT? The correct answer is highlighted below Distruption of electrical current Conductivity measurement using high frequency electromagnetic probe Forward angle light scatter Lysis of white cells with subsequent conversion to cyanmethemoglobin followed by spectrophotometric determination
Lysis of white cells with subsequent conversion to cyanmethemoglobin followed by spectrophotometric determination Distribution of electrical current, conductivity, and light scatter are all used to quantitate and differentiate white blood cells. The cyanmethemoglobin method is used to measure hemoglobin, not white cells.
The appropriate magnification for a manual RBC cell count using a hemocytometer is which of the following? The correct answer is highlighted below 10X 100X (Oil) 40X (Dry) 4X
Manual RBC counts, manual WBC counts, and WBC estimates on a peripheral blood smear are all performed on 40X (dry). 10X is used to assess color, rouleaux, overall slide quality, and cell distribution of a peripheral blood smear. 100X (Oil) is used for platelet estimates to assess RBC, platelet, and WBC morphology, WBC differential, and RBC inclusions on peripheral blood smears. 4X is rarely used in hematology and is most commonly used to look at tissue.
Which of the following tests would be most affected by microclots in an EDTA tube drawn for a CBC? The correct answer is highlighted below RBC Hematocrit Hemoglobin Platelet count
Microclots are mainly made up of clumped platelets. Therefore, the platelet count will be falsely decreased as hematology analyzers would not be able to count the individual platelets in the clumps. A large clot in the sample would falsely decrease the RBC count and hematocrit, but microclots would not affect these parameters as much as the platelet count. Hemoglobin would not be affected by microclots.
A smear that is prepared from equal parts of new methylene blue and whole blood is used for which of the following? The correct answer is highlighted below WBC differential Platelet estimate Reticulocyte count Manual RBC count
New methylene blue is a supravital stain used to visualize remnant cytoplasmic RNA and organelles (e.g., mitochondria, ribosomes) in reticulocytes. A WBC differential and platelet estimate should be performed from a Romanowsky-stained (e.g., Wright-Giemsa) peripheral blood smear. Manual red blood cell counts are occasionally performed using a hemacytometer. Specimens are typically left unstained before analysis.
How many 1 mm x 1 mm squares is the Neubauer hemacytometer counting grid composed of? The correct answer is highlighted below Nine per side Ten per side Twenty-two between both sides Thirty between both sides
Nine per side The hemacytometer is composed of two 3 mm x 3 mm square counting grids. Each 3 mm x 3 mm counting grid is composed of nine 1 mm x 1 mm squares, for a total area of 9 mm2 per grid. The depth of the counting grid is 0.1 mm, making the total volume of each grid 0.9 mm3.
Which of the following statements is FALSE? The correct answer is highlighted below White blood cell counts increase more in bacterial septicemia than in viral meningitis. Nucleated red blood cells can cause a falsely decreased white blood count. An acceptable blood smear (i.e., peripheral smear) will have a feathered edge. Normal cell count values often differ among age groups.
Nucleated red blood cells actually cause a falsely elevated WBC count as they are often counted as white cells during automated CBC analysis. White blood cell counts do increase more in bacterial septicemia than in viral meningitis due to the fact that in bacterial infections, there is an increase in neutrophils which comprise the largest portion of the WBC differential. Lymphocyte counts are typically increased in viral infections, but not necessarily to the extent of increasing the total WBC count. The thin portion of a well-made peripheral smear should have the appearance of a "rainbow" when the slide is held up to the light. This thin portion is known as the feathered edge. The individual's age has a definite effect on normal cell counts; thus, this variation is reflected in reference ranges in clinical laboratories. In most facilities, there are different reference ranges based on age groups.
What would be the next step when an EDTA specimen had an automated platelet count of 61,000/mm3 and the platelets were surrounding the neutrophils on the differential? The correct answer is highlighted below Report the automated platelet count since it is more accurate than a platelet estimate Warm the EDTA tube and repeat the automated platelet count Rerun the original specimen since the platelet count and blood smear estimate do not match Recollect a specimen for a platelet count without using EDTA
Occasionally platelet satellitosis can occur in some patient samples when collected in EDTA. The solution for this problem is to recollect in a different type of anticoagulated tube, usually a sodium citrate tube, to prevent the platelets from adhering to the neutrophils. The platelet count would be multiplied by 1.11 to account for the dilution of the blood sample with sodium citrate (9:1).
Which laboratory result is the most critical in recognizing heparin-induced thrombocytopenia (HIT)? The correct answer is highlighted below Fibrinogen level Prothrombin time D-dimer Platelet count
Patients receiving heparin therapy should have periodic platelet counts to detect possible HIT. In certain patients, HIT can be caused by the development of antibodies that activate platelets in the presence of heparin. These antibodies can also cause vascular injury resulting in life-threatening thrombosis. Fibrinogen and Prothrombin tests detect coagulation factors and thus are not helpful in determining platelet status. D-dimer does detect thrombosis, but this test would not give any indication as to the cause of the thrombosis.
What is the BEST type of microscopy for performing manual platelet counts? The correct answer is highlighted below Electron Dark-field Light Phase contrast
Phase-contrast microscopy can help to better define the outline of the platelets over regular light microscopy, making them easier to count and allowing for more accurate results. Dark-field and electron microscopes are not used for platelet counting. Electron microscopy uses a beam of electrons to create an image of the specimen and is capable of higher magnifications than light microscopy. Dark-field microscopy has the light source blocked, causing light to scatter as it hits the specimen. It is used for refractive elements and allows illumination of the specimen against a dark background. Light microscopy is used when performing cellular estimates or differentials with a stained specimen at various magnifications, most commonly 10x, 100x, and 1000x.
All of the following methods are used in the diagnosis and classification of acute leukemia, EXCEPT? The correct answer is highlighted below Immunophenotyping Reticulocyte count Cytochemical Analysis Cytogenetics
Reticulocyte counts are a measure of immature erythrocytes, which can be present in many forms of hematologic disorders. While this procedure can be useful in monitoring a leukemic patient's status, it is not useful in the diagnosis of acute leukemia. Immunophenotyping is used to identify the lineage of blasts in acute leukemia based on cell markers. Cytochemical analysis of the leukemic cells can be used to help classify the types of cells present in an acute leukemia and is especially helpful in quickly determining if myeloid or lymphoid lineage. Cytogenetics is useful in the diagnosis and classification of acute leukemias because certain forms are consistently associated with specific chromosome changes.
The diagnostic value of the reticulocyte count in the evaluation of anemia is that it determines the: The correct answer is highlighted below Response and ability of the bone marrow to compensate for the anemiaNutritional status of the patientReal cause of the anemiaTrue red blood cell count
Reticulocyte counts can help determine how well the bone marrow is responding and it's potential to make new RBCs. For example, an increased reticulocyte count could show the physician that the medication given to a patient to treat their anemia is working since the bone marrow is releasing new, young RBCs (reticulocytes). Although lower reticulocyte counts can be found in various anemias such as iron deficiency or B12 deficiency anemias, the reticulocyte count alone is not diagnostic, nor it determines the nutritional status of the patient. Reticulocyte counts can only indicate the degree to which the bone marrow is attempting to compensate and can not determine the specific cause. Reticulocytosis is often associated with hemolytic anemias but is also seen in patients recovering from other causes of anemia. The reticulocyte count only gives the number of new, immature red blood cells, and is not indicative of the total red blood cell count.
Which one of the following hematological determinations is MOST reliable for evaluating bone marrow erythropoietic activity? The correct answer is highlighted below Hemoglobin Reticulocyte count Platelet count Mean corpuscular volume
Reticulocyte counts evaluate the activity of the bone marrow, particularly in terms of erythropoiesis. As the bone marrow is attempting to recover from an abnormal hematological state (i.e., anemia), there are more reticulocytes produced. Reticulocyte counts are often used to evaluate the effectiveness of therapy for stimulating the bone marrow. Hemoglobin level is an indicator of the degree of anemia, but it does not correlate with bone marrow activity. Platelet count only indicates the degree of platelet production. Thrombocytosis may also be associated with hemorrhage, post-surgery, or post-splenectomy. Mean corpuscular volume (MCV) may slightly increase as more reticulocytes are released. But this is not a reliable indicator for bone marrow activity.
Which of the following statements characterize a reticulocyte? The correct answer is highlighted below Reticulum visible with a supravital stain, such as new methylene blue Reticulum visible with Wright stain Contains some organelles used for hemoglobin production Pyknotic nucleus still present in the cell
Reticulum visible with a supravital stain, such as new methylene blue Reticulum is not visible with a Wright stain. Reticulocytes appear blue-gray on a Wright-stained smear and are referred to as polychromatophilic red cells. If a manual reticulocyte count is performed, a supravital stain, such as new methylene blue, must be used to stain reticulocytes. The reticulocyte contains numerous organelles needed for hemoglobin production, such as ribosomes, mitochondria, and fragments of the Golgi apparatus. A reticulocyte normally remains in the bone marrow for one or two days before entering the circulation and its final 24 hours of maturation. The red cell is mature when hemoglobin production is complete and the organelles have disintegrated.
In reference to semen analysis microscopic examination, differentiation, and enumeration of "round cells" which are often present in semen count are referred as: The correct answer is highlighted below Sperm vitality Seminal fluid fructose White blood cells (WBCs) Bacteria
Round cells refer to WBCs or immature sperm cells in a semen sample. These cells can be differentiated on a stained smear, using 1000X magnification, or more precisely by performing a peroxidase assay. An increased number of WBCs present indicates inflammatory conditions associated with infection and poor sperm quality. Sperm vitality and seminal fluid fructose are the types of additional testing done when abnormalities are suspected in sperm morphology and functionality. The presence of Bacteria in the seminal analysis may be indicative of an infection.
A semen specimen was collected three hours before it was brought to the laboratory for examination. What course of action should be taken? The correct answer is highlighted below Complete macroscopic and microscopic examination as quickly as possible. Report the specimen as compromised on the final report. Perform the macroscopic and morphology procedures only. Perform the wet mount only.
Since the recommended time limit between collection and analysis is one hour, at three hours, the technologist should report the specimen as compromised on the final report. The semen specimen is examined under a microscope to determine the concentration, motility (movement), and morphology (appearance and shape) of the sperm. Since it is important to observe the sperm while they are still active, samples must be received for analysis within an hour.f
All of the following can cause erroneously decreased automated platelet counts EXCEPT? The correct answer is highlighted below Platelet clumping Platelet satellitosis Clotting WBC fragmentation
Spurious/erroneous decreases in automated platelet counts can be caused by clotting, platelet satellitosis, and platelet clumping. Spurious/erroneous increases in automated platelet counts can be caused by cryoglobulin, cyrofibrinogen, white cell fragments, and hemolysis.
A WBC differential count on CSF should be performed using the following technique: The correct answer is highlighted below Wet mount of sample from collection tube Stained smear of a cytocentrifuged specimen Directly from hemocytometer chamber count Directly from stained hemocytometer count
Stained smear of a cytocentrifuged specimen Differential counts on CSF should be performed on stained smears made from a cytocentrifuged specimen. The cytocentrifugation process distributes the cellular elements in a monolayer, making it easy to distinguish the cells' morphology when observed under the microscope. Cell type cannot be reliably assessed on unstained specimens or from the hemocytometer.
A hemocytometer is generally used for all of the following, EXCEPT? The correct answer is highlighted below Cell counts in CSF Synovial fluid crystal counts RBC/WBC counts Platelet counts
Synovial fluid crystals are best examined fresh using only a slide and coverslip, and a polarizing microscope. For all the other counts listed, a hemocytometer can be used to count the respective cells.
Which of the following represents the percent population of T-helper cells in this sample data? absolute lymphocyte count= 2.4 x 109/L %CD3 = 60 %CD4 = 40 %CD8 = 20 The correct answer is highlighted below 60% 40% 20% 80%
T-helper cells are CD4 positive. The flow results reflected 40% CD4.CD3 is a pan T cell marker (and should reflect CD4 plus CD8).CD8 is the cytotoxic/suppressor T cell marker.
Laboratory results obtained on a 47-year-old patient were as follows: WBC 51.2 x 103/µL RBC 4.27 x 106/µL HGB 12.6 g/dL HCT 36.9% PLT 403 x 103/µL Differential: 50% segmented neutrophils 20% bands 12% lymphocytes 7% monocytes 1% eosinophils 9% metamyelocytes 1% myelocytes RBC morphology: normocytic, normochromic WBC morphology: moderate toxic granulation, slight Dohle body Which test would be MOST helpful in establishing a diagnosis in this case? The correct answer is highlighted below Leukocyte alkaline phosphatase stain (LAP stain) Nonspecific esterase stain Acid phosphatase Sudan black B
The LAP stain is used to determine if an increase of cells is due to Chronic Myelogenous Leukemia or a leukemoid (noncancerous) reaction such as an infection. Cells from a leukemoid reaction stain positive with many intense blue granules, while cells from chronic myelogenous leukemia have few blue granules. Although chromosomal studies are generally used to distinguish CML based on the Philadelphia chromosome, the LAP stain is still a reliable method to distinguish leukemoid reaction. Esterase stains are used in detecting monocytes, macrophages, and histiocytes and are not helpful in distinguishing cells in the neutrophilic line. Acid phosphatase stains are useful in distinguishing lymphocytes from other mononuclear cells. Sudan back B is useful in distinguishing cells in the myeloid line from those in the lymphoid line.
What does the M:E ratio in a bone marrow evaluation represent? The correct answer is highlighted below Monocytes to erythrocytes Myeloid cells to erythroid cells Myelocytes to erythrocytes Megakaryocytes to erythrocytes
The M: E ratio stands for the Myeloid: Erythroid ratio. This represents the relationship between myeloid cells and erythroid cells in a bone marrow evaluation. The myeloid cells include all granulocytes and their precursors. The erythroid cells include all nucleated red cell precursors. Megakaryocytes are evaluated by scanning the bone marrow aspirate smear but are not included in the M:E ratio. Non-nucleated erythrocytes, monocytes, lymphocytes, and plasma cells are not included in the M:E ratio.
Which of the following represents the White Blood Cell (WBC) count reference range for adults? The correct answer is highlighted below 4.4 - 11.0 x 109/L 0.5 - 1.5 % 150 - 450 x 109/L 140 - 200 mg/dL
The White Blood Cell (WBC) reference range for an adult is 4.4 to 11.0 x 109/L. The WBC count can be increased in cases of acute infection, leukemia, and mononucleosis. 0.5 to 1.5% represents the reference range for a retic count. 150 - 450 x 109/L represent the adult reference range for platelet counts. 140 - 200 mg/dL represents the adult reference range for cholesterol.
Which of the following formulas would you use to calculate absolute cell counts? The correct answer is highlighted below Cells counted / total cells 10 x cells counted / total cells Total count X % of cells counted Cells counted X total cells
The absolute cell count is the percentage of a single leukocyte type multiplied by the total WBC count.
Which of the following descriptions best describes the term absolute value as it would relate to leukocyte differential counts. The correct answer is highlighted below Relative % of each cell type Relative % of each cell type multiplied by total white count Relative % of each cell type divided by total white count Specific number of each cell type divided by total white count
The absolute cell counts are measurements calculated by multiplying the relative cell percentages by the total white blood cell count.
When preparing a slide for morphologic examination, what is the reason for adding a drop of albumin to the cerebrospinal fluid (CSF) sample prior to cytocentrifugation? The correct answer is highlighted below Enhance staining of the elements. Preserve the integrity of the cells. Increases the fluid volume so that cells will form a monolayer on the slide. Dilute the sample
The addition of a drop of 30% albumin helps to preserve the integrity and morphology of the cells in the hypotonic CSF. Albumin is not used to enhance the stain or dilute the sample. The cytocentrifugation process distributes the cellular elements in a monolayer.
A technologist decides to make a 1:20 dilution of cerebrospinal fluid (CSF) after briefly evaluating a portion of the sample microscopically. After making the dilution and charging the chambers, the number of observed cells in each of the large squares of the hemocytometer is >100. What should the technologist do to obtain the most accurate count? The correct answer is highlighted below Count all four corner squares. Make a smaller dilution. Make a larger dilution. No dilution is necessary.
The best choice would be to make a larger dilution before performing the cell count. This will provide the most accurate results.
Pleural fluid was sent to the laboratory for a WBC count. The specimen was NOT diluted. WBCs in 5 large squares were counted in each side of the hemacytometer. The number of WBCs counted were as follows: Top counting chamber: 35 cells total (in 5 large squares) Bottom counting chamber: 33 cells total (in 5 large squares) Based on the information provided above, calculate the total WBC count. The correct answer is highlighted below 34 cells/mm3 3.4 cells/mm3 680 cells/mm3 68 cells/mm3
The calculation of the cell count is based on the formula: Total cells/µL = (total number of cells counted x dilution factor) / (total number of squares counted x volume of each square) Each large square has a length of 1mm, width of 1mm and a depth of 0.1mm Thus, the volume of each large square is 1mm x 1mm x 0.1mm = 0.1mm3 In this example, we would calculate: total cells/µL = (68 cells) / (10 x 0.1mm3) 68 cells/mm3 or 68 cells/µL
The site most frequently used to collect bone marrow samples from adults is: The correct answer is highlighted below Sternum Anterior iliac crest Posterior iliac crest Tibia
The posterior iliac crest is the most common site for bone marrow aspiration and core biopsies. This site provides adequate marrow and is isolated from anatomical structures that are subject to injury. The sternum provides ample material for aspiration in adults but cannot be used for core biopsies due to the proximity of the heart and large blood vessels. The anterior iliac crest is occasionally used for patients who can only lie in the supine position. The cortical bone is much thicker than the cortical bone of the posterior iliac crest and may be more difficult to obtain high-quality specimens. The anterior iliac crest can be used for aspirates and core biopsies. The anterior medial surface of the tibia may be used for pediatric patients under two years of age. It is only used for aspirates.
You are working in a hematology laboratory, and the machine flags an outlier result for a 51-year-old male. The blood was collected in an EDTA tube for a CBC. The hematocrit of the specimen is high at 60%. Which of the following would you do? The correct answer is highlighted below Collect blood again, but use less sodium citrate in the tube. Collect blood in heparin. Report these results. Assume that the specimen was switched with that of a newborn child.
The correct answer is: report these results. There may be several reasons for a high hematocrit - including the obvious possibility that this is a newborn (normal hematocrit range of 55-68%). Another likely reason for a high hematocrit is dehydration - the individual happens to have less fluid in the body. Less frequent causes include Polycythemia Vera or high hematocrit due to blood doping. The first choice, "collect blood again, but use less sodium citrate in the tube," is wrong for two reasons: (1) you use EDTA rather than sodium citrate for CBC blood collection and (2) blood collection is a standardized practice and thus your goal in testing the hematocrit is to determine the actual hematocrit - not to artificially disturb the ratio of anticoagulant to arrive at a normalized determination of hematocrit. The second choice, "collect blood in heparin," is wrong because you don't collect CBC specimens in heparin - you use EDTA. While it is true that this hematocrit falls within the normal range of a newborn, 60% is not so tremendously high (normal hematocrit for an adult male is 42-52%) that you ought to assume that specimens have been switched.
Given the following information, what is the CORRECTED white count? Initial White count = 35,000/µL 92 nucleated red blood cells are noted per 100 WBC's counted on the manual differential The correct answer is highlighted below 3,500/µL 10,300/µL 16,700/µL 18,229/µL
The corrected WBC count is calculated by utilizing the following formula: Uncorrected WBC count x 100 NRBC's per 100 WBC's + 100 35,000 x 100 = 18,229/µL 92 + 100
What is the corrected WBC if a differential count shows 20 nucleated erythrocytes per 100 leukocytes and the uncorrected leukocyte count is 12.0 X 109 The correct answer is highlighted below 1.0 X 109/L 2.0 X 109/L 10.0 X 109/L 12.0 X 109/L
The formula for correcting a white blood cell count in the presence of more than 5 nucleated red blood cells per 100 white blood cells is: (Uncorrected WBC countx100) /(# NRBCs per 100 WBCs + 100) (12.0 X 109/L X 100) / (20 + 100) = 10.0 X 109/L or 12,000/cu mm X 100 / 20 + 100 = 10,000/cu mm
A 1:100 dilution of a patient's peripheral blood was made, and a total of 136 platelets were counted in 5 squares of the RBC area of a Neubauer-ruled hemocytometer. What is the Platelet count? Note: The volume correction factor is 50 µL. The correct answer is highlighted below 27 x 103/µL 68 x 103/µL 136 x 103/µL 680 x 103/µL
The general formula for calculating cellular elements on a Neubauer hemocytometer is as follows: Count = [(Dilution Factor) x (Total cell count in 5 RBC squares] x (Volume Correction Factor) Count = (100 x 136) x 50 = 680,000 or 680 x 103/ µL
A manual platelet count was performed using a Neubauer hemacytometer. The total platelet count was 356 x 103/µL. A platelet estimate was then performed on the peripheral blood smear. Ten fields were counted and yielded the following results: 17, 16, 15, 20, 19, 17, 19, 16, 20, 18. The platelet estimation factor for the microscope used was 20,000. What is the next logical step? The correct answer is highlighted below Report the manual platelet count since it correlates well with the platelet estimate Repeat the hemacytometer count on a recollected specimen and check for clumping Check ten additional fields on the peripheral blood smear Repeat the platelet count using a different method
The platelet estimate is calculated as follows: ((17 + 16 + 15 + 20 + 19 + 17 + 19 + 16 + 20 + 18)/10) x 20,000 = 354,000/µL (354 x 103/µL) The accuracy of a manual platelet count should be verified by performing a platelet estimate on the peripheral blood smear. In this case, the platelet estimate correlates well with the manual platelet count; therefore, the manual platelet count should be reported. There is no reason to recollect the specimen unless platelet clumping or platelet satellitosis is noted. If noted, specimens should be recollected as stated in standard operating procedures. Note that specimens with platelet clumping or platelet satellitosis commonly have total platelet counts less than 50 x 103/µL when automated methods are used. Checking ten additional fields or repeating the platelet count using a different method is not necessary in this case.
Blast cells found in a spinal fluid differential are most likely associated with which of the following? The correct answer is highlighted below Bacterial meningitis Acute Leukemia Viral meningitis Metastatic carcinomas
The presence of blast cells in the differential of spinal fluid is usually associated with acute leukemia. The presence of a high number and percentage of neutrophils can be associated with bacterial meningitis. The presence of a high number and percentage of lymphocytes can be associated with viral meningitis. Malignant cells found in spinal fluid can be associated with metastatic carcinomas.
A 40-year-old man patient presents with non-specific physical complaints which include abdominal pain. Based on symptoms and family history the physician suspects Hereditary Hemochromatosis. Which of the following laboratory tests would be the LEAST diagnostic? The correct answer is highlighted below Complete blood count Liver function tests Genetic studies Iron studies
The purpose of laboratory testing for suspected hereditary hemochromatosis is to screen for the condition (iron studies), diagnose the cause and degree of organ damage (liver function test), pinpoint the mutation (genetic testing), and monitor treatment. Although the CBC may be an effective screening test for many conditions and would most likely be a part of routine screening, it would have little effect on the diagnosis of hemochromatosis.
The role of the medical laboratory scientist in processing bone marrow aspirates can vary depending on laboratory and clinician protocols. Which of the following statements is true regarding the bone marrow procedures typically performed by an MLS? The correct answer is highlighted below They prepare the patient for the bone marrow procedure. They perform the bone marrow aspiation and biopsy. They make and/or stain the bone marrow smear. They examine and interpret the bone marrow smear.
They make and/or stain the bone marrow smear. The MLS or laboratory technologist's role may include making smears, either at the patient bedside or in the laboratory and staining the smears. They do not prepare the patient, perform the procedure, or interpret the results. Typically a nurse prepares the patient for the procedure. The clinician or pathologist obtains the bone marrow samples, which include aspirates or biopsies. The pathologist then examines and interprets the bone marrow smear.
Two CSF specimens were sent to the Lab with the following results: Tube #1 = 11,200 rbc/µL Tube #2 = 300 rbc/µL The results on these CSF specimens are indicative of: The correct answer is highlighted below An infection A recent subarachnoid hemorrhage A traumatic tap An old intracranial bleeding episode
Traumatic taps are described as spinal fluid taps where blood vessels are pierced with the needle during aspiration, causing a contamination of the spinal fluid sample with blood or bone marrow. Traumatic taps are easily differentiated from true hemmorhages as each subsequent container of spinal fluid drawn will have a smaller amount of red and white cells present. In a true hemorrhage, the red and white cell counts will remain steady in each subsequent tube of spinal fluid drawn.
Cerebrospinal fluid (CSF) specimens are usually collected by lumbar puncture and placed in numbered tubes starting with the first tube collected. If four tubes are collected, which tube would be used for a cell count and differential? The correct answer is highlighted below Tube #1 Tube #2 Tube #3 Tube #4
Tube #3 is the most commonly used CSF tube for hematology for cell counts and differential. Cell counts -- particularly WBC counts -- are a critical part of CSF testing. Tube #1 is delivered to Chemistry or Serology. This tube may contain some contamination caused by the passage of the puncture needle through the skin to the spinal canal. This contamination does not contain substances that can interfere with the tests performed in these departments. Tube #2 is delivered to Microbiology for Gram stain and culture. Tube #4 is usually reserved for additional, more specialized testing.
When performing a manual white blood cell count, 236 cells were counted on side number one of the hemacytometer, 224 cells on side number two. A 1/20 dilution of 1% HC1 was used, and the area counted on each side was 4 sq. mm. Twenty-five nucleated red blood cells in the differential were observed per 100 white blood cells. What is the CORRECT WBC/µL? The correct answer is highlighted below 8,500 9,200 9,575 12,425
WBC calculation = ((# of Cells Counted X Dilution Factor X Depth Factor) / (# of Square Millimeters Counted)) = WBC per mm3 Average of 236 + 224 = 230 dilution factor = 20 area counted = 4 mm2 So... 230 cells x 20 x 10 / 4 = 11,500 Corrected WBC count calculation = uncorrected WBC count x 100 / # of NRBCs +100 So... 11,500 x 100 / 25 + 100 = 9,200
A manual white blood cell count was performed by the hematology technologist. The cell counts for both sides were 99 and 164, respectively. All nine large squares were counted on each side. The dilution for this kit was pre-measured at 1:100. What should the technologist report as the white cell count? The correct answer is highlighted below 14.61 x 109/L 1.46 x 109/L 4.61 x 109/L Cannot report
When comparing the white cell counts from one side of the hemacytometer to the other, there is not good duplication. Cell counts from opposite sides of the hemacytometer (within the same patient sample) that are greater than 10% of one another are considered discrepant and should not be used to calculate reportable results. This particular count should not be used to report patient results.
When three tubes of cerebrospinal fluid are received in the laboratory they should be distributed to the various laboratory sections as follows: The correct answer is highlighted below #1 Hematology, #2 Chemistry, #3 Microbiology #1 Chemistry, #2 Microbiology, #3 Hematology #1 Microbiology, #2 Hematology, #3 Chemistry #1 Chemistry, #2 Hematology, #3 Microbiology
When three tubes of CSF are collected, the first tube is used for chemical and/or serological analysis. The second tube is used in microbiology in order to prevent any contamination of the bacterial culture by skin microbiological flora that may have occurred during the insertion of the spinal needle during the collection process. The last tube (#3) should always be used for hematology studies in order to minimize the effect of any peripheral blood (traumatic tap) contamination that may have occurred during the insertion of the spinal needle.