MLT HEMATOLOGY
Anti-H:
D. Reacts more strongly with group A2 cells than with group A1 cells Feedback A2 cells contain more H antigen than A1 cells.
When performing controls for the morning run in coagulation, the normal control is within acceptable limits for both PT and APTT, but the abnormal control is out of range for both procedures. Appropriate action would be to:
D. document the out of range QC, repeat the abnormal control, troubleshoot if necessary; report patient results only when both controls are within acceptable ranges. Feedback When coagulation controls are out of range, the technologist must document the situation first. Then the problem must be resolved by repeating, opening a new lot, calibration, etc. Only when the issue has been resolved and the coagulation controls are BOTH within range, can the patient samples be analyzed and resulted.
Which test result will be normal in a patient with dysfibrinogenemia?
D. fibrinogen level Feedback In dysfibrinogenemia, fibrinogen levels are normal; however, the fibrinogen has a functional impairment. About 1 person in 1 million is affected by this condition. The PT, aPTT, and TT tests will be prolonged in cases where fibrinogen is dysfunctional.
A two-year old male patient has the following hemogram results: Hgb = 6.7gms/dl Hct = 20% Platelets = 355,000/ mm3 RBC = 3.0mil/cmm WBC = 8750/cmm Differential = 6 eos 20 segs 68 lymphs 6 monos
Dietary iron deficiency Feedback We can rule out answer Idiopathic thrombocytopenia since the platelet count is normal. We can also exclude lymphocytic leukemia because the WBC is normal. Thalassemia minor can be excluded because thalassemia patients usually have only mild anemia. Finally, lead poisoning cannot be the answer since this condition does not usually cause severe anemia. The RBC, Hct, and Hgb are all very low, and this fits the picture of iron deficiency anemia.
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?
B. 9,837 wbc Feedback Corrected WBC count = uncorrected WBC count x (100 / NRBCs +100) Corrected WBC count = 14,460 x (100/147) = 9,837
Hemoglobinopathies can be caused by all of the following structural defects EXCEPT: A. Deletion of a globin chain. B. Substitution of amino acids in a globin chain. C. Deletion of an amino acid in a globin chain. D. Addition of an amino acid in a globin chain. E. Fusion of globin chains.
A. Deletion of a globin chain. Feedback Hemoglobinopathies are not caused by deletion of a globin chain. Partial and complete deletions of globin chains lead to thalassemia. Substitution of amino acids in a globin chain is the most common cause of hemoglobinopathies. Deletion or addition of an amino acid in a globin chain, or fusion of globin chains will also cause hemoglobinopathies.
What are the erythrocyte inclusions that are indicated by the arrows on this blood smear?
A. Howell-Jolly bodies Feedback The small, spherical, dark blue-staining, non-refractile inclusions are known as Howell-Jolly bodies. They may represent chromosomal remnants, and may be found in pernicious anemia, hemolytic anemias, and after splenectomy.
A patient admitted to the hospital for ongoing fever produces the following laboratory results: RBC count: 3.56 x 1012/L WBC count: 57.5 x 109/L Platelet count: 375,000/uL Differential count: 3 blasts, 10 myelocytes, 6 metamyelocytes, 12 bands, 64 segs, 4 lymphocytes, and 1 monocyte LAP score = 155. Which of the following conditions correlates closely with this patient's results?
A. Leukemoid Reaction Feedback A high white blood cell count, usually 50-100 x 109/L with a left shift is a common finding in leukemoid reactions. In addition, a key feature of a leukemoid reaction is a high LAP score. Chronic Myelogenous Leukemia (CML) is highly associated with the Philadelphia chromosome, or translocation (9;22)(q34;q11). CML typically shows a low LAP score, in contrast to the findings in this case. Finally, Paroxysmal Nocturnal Hemoglobinuria (PNH) is also associated with a low LAP score, which excludes this as the correct answer.
The diagnostic value of the reticulocyte count in the evaluation of anemia is that it determines the:
A. response and potential of the bone marrow Feedback Reticulocytes counts can help determine how well the bone marrow is responding and its potential to make new RBCs. For example, an increased retic count could show the physician that the medication given to a patient to treat his/her anemia is working since the bone marrow is releasing new, young RBCs (reticulocytes).
The peripheral blood picture is consistent with each of the following conditions except:
Abetalipoproteinemia Feedback The correct response is abetalipoproteinemia. While the majority of red blood cells in abetalipoproteinemia are acanthocytes, the peripheral blood smear that is pictured here contains only an occasional acanthocyte (the cell that is tagged by the arrow), an amount not consistent with abetalipoproteinemia. Acanthocytes in lesser numbers are found in advanced liver disease, in newborn hepatitis, and following splenectomy when there is reduced removal of these poikilocytes.
ACQUIRED hemophilia A may be the result of which of the following conditions?
Anti-factor VIII inhibitor Feedback Patients with acquired hemophilia A are suffering from a coagulation inhibitor, specifically against factor VIII. Inherited hemophilia A is caused by a deficiency in factor VIII. Neither warfarin therapy nor thrombosis complications can cause acquired hemophilia.
When three tubes of cerebrospinal fluid are received in the laboratory they should be distributed to the various laboratory sections as follows:
B. #1 Chemistry, #2 Microbiology, #3 Hematology Feedback When three tubes of CSF are collected, the first tube is used for chemical and/or serological analysis, the second tube is used to prevent contamination of the bacterial culture by skin germs or flora. The last tube (#3) should always be used for hematology studies in order to minimize the effect of any peripheral blood contamination which may have occurred during the insertion of the spinal needle.
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?
B. 17.5 x 10^9/L Feedback 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 (1mm2) X 0.1mm (depth factor) So, in this problem: 158 x 100 / 9 x 1 x 0.1mm = 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
A patient has a prolonged non-therapeutic PT and a normal aPTT. The physician orders a PT mixing study. The results are as follows: Original PT test- 32 seconds 1:1 Mix (room temp immediate) - 22 seconds 1:1 Mix (incubated for 90 minutes) - 23 seconds Which factor may be present in abnormally low levels and causing the prolongation?
B. Factor VII Feedback The only factor listed that could cause a prolongation of the PT test if the aPTT test is normal is factor VII. Factor VII along with the common pathway factors are monitored by the PT test. However, the aPTT test is normal. Therefore, no factor in the common pathway would be deficient. Factors VIII, IX, and XI are all factors of the intrinsic pathway and are evaluated with the aPTT test.
On an electronic cell counter, hemoglobin determination may be falsely elevated caused by the presence of:
B. Leukocytopenia or Leukocytosis Feedback Since hemoglobin is measured spectrophotometrically on hematology analzyers, interference from lipemia or icteric specimens can lead to decreased light detected and measured through the sample and therefore inaccurate hemoglobin results occur.
Which of the following test results are NOT characteristic of disseminated intravascular coagulation (DIC)?
B. Negative test for fibrin split products Feedback Fibrin split products (FSP) and d-dimers are fragments of protein released from a clot that has been broken down by fibrinolysis. In DIC, the coagulation cascade is triggered abnormally, resulting in the coagulation system being overwhelmed with excessive clotting and fibrinolysis taking place. This process of over clotting and over dissolving creates increased fibrin split products and d-dimers, the opposite of the choice above. Decreased fibrinogen levels, decreased platelet count, and prolonged PT tests are all associated with DIC and the consequences of over clotting and over dissolving.
A definitive diagnosis of malaria can be made by:
C. Demonstration of the organisms in peripheral blood Feedback Diagnosis of malaria may require thick smears as well as conventional thin blood smears.
Which of the following is an important technique consideration in order to obtain consistently high quality bone marrow smears?
C. Select or concentrate bone marrow spicules, ensuring they are transferred to the slide. Feedback In order to obtain consistently high quality smears, it is necessary to select or concentrate the bone marrow spicules (fragments). Selecting or concentrating fragments can be performed with different methodologies. At the patient bedside, some clinicians will use the touch-preparation or pull-preparation method, while tilting the slide to allow excess blood to roll off. This leaves more of the bone marrow spicules on the slide. This can be wasteful and rather messy but does not require a high level of skill. A less wasteful method is to pour a portion of the marrow aspirate into a small petri dish and swirl it about, then tilt the dish to reveal the marrow spicules. These can then be extracted using a capillary pipette with a micro-pipette bulb and transferred to the slide for use in making smears. This technique allows the laboratory professional to make numerous smears containing fragments rather than relying on the random luck of the drop. You would not want to use a very large drop of marrow as this would probably not smear out to a readable layer of cells. Slides can be prepared at the patient bedside if the work area is prepared sufficiently to ensure slides can be easily made. Making slides at the patient bedside is also dependent on hospital policy. It is important to prepare as many slides as possible from the obtained sample to provide the opportunity for choosing the best quality slides and for special stains, if needed.
In the hemoglobin methodology using potassium ferricyanide the following measurable reaction occurs:
C. ferrous iron is oxidized to ferric iron to form methemoglobin Feedback In an alkaline medium, potassium ferricyanide oxidizes hemoglobin to methemoglobin. Further reaction with potassium cyanide produces cyanmethemoglobin which has a maximum absorbance at 540 nm. Color intensity is proportional to total hemoglobin concentration, which is how the hemoglobin levels are measured.
Which FAB designation is called the "true" monocytic leukemia and is characterized by monoblasts, promonocytes, and monocytes?
FAB M5 Feedback FAB M5 is acute monoblastic leukemia FAB M1 is acute myeloblastic leukemia without maturation FAB M3 is acute promyelocytic leukemia FAB M4 is acute myelomonocytic leukemia
After the physician orders a follow up for abnormal coagulation screening tests, the laboratorian completes a mixing study with the following results: Initial aPTT result: 98 seconds Initial 1:1 Mix with Normal Pooled Plasma: 28 seconds Incubated 1:1 Mix with Normal Pooled Plasma: 30 seconds Which of the choices below would most likely explain the results for this patient?
Factor VIII deficiency Feedback The only correct answer of the choices listed above is the presence of a factor VIII deficiency. Factor deficiencies are usually corrected during the mixing study when normal pooled plasma is added to the sample. The normal pooled plasma contains high enough levels of coagulation factors to correct the deficient level in the patient sample, causing a normalized aPTT result. In this case, it could not be a factor VII deficiency, as this coagulation factor is measured in the PT assay alone. There is also no coagulation inhibitors present (either immediate-acting or time/temperature-dependent) as the aPTT mix would not have displayed this pattern of correction.
Which two of the following are associated with macrocytic anemia?
Fish tapeworm Folic acid deficiency Feedback Both fish tapeworm and folic acid deficiency may appear as a macrocytic anemias.
During the flow cytometry analysis process, cells exiting the flow cell intersect a laser, and produce what kind of data?
Intrinsic cell characteristics Extrinsic cell characteristics Forward scatter Fluorescence As cells exit the flow cell in single file, they intersect the laser and emit the following data: Intrinsic cell characteristics Size (forward scatter) Granularity (side scatter) Extrinsic cell characteristics Surface Antigens (fluorescence emitted by the MoAb bound to the specific antigens)
What changes Fibrinogen into Fibrin Monomer:
Thrombin Feedback Thrombin converts fibrinogen to fibrin monomers. These polymerize to form a fibrin clot, which is then covalently crosslinked by activated factor XIII (fibrin-stabilizing factor).
True/False The nuclear appendage (Barr Body) at the tip of the arrow is a normal finding in females but not in males.
True Feedback The small drumstick-like nuclear extension (Barr body) marked by the blue arrow is a chromatin mass which may represent a chromosomal remnant. These nuclear appendages are found in normal XX females, but would not be present in normal XY males. If such an appendage is found in a phenotypic male, Klinefelter's syndrome (XXY male) may be identified clinically. The appendage has a "drumstick" morphology.
The peroxidase stain is useful in differentiating between which cells?
lymphocytic and granulocytic cells Feedback Peroxidase stain is an enzymatic stain based on the principle that peroxidase granules in some neutrophils and in eosinophils will stain positive. Lymphocytes stain negative with peroxidase stains.
Pappenheimer bodies are usually seen in patients who have:
splenectomies Feedback Pappenheimer bodies can be found in patients who have had a splenectomy since the spleen typically removes these cells from the peripheral blood. Therefore, if the spleen is no longer present, these cells can be found in peripheral smears.
