Unit 1 Objectives
Recognize complete blood count (CBC) data that indicate the presence of interfering substances such as lipemia and cold agglutinins.
-Cold agglutination and lipemia are 2 suspects when MCHC is over 37. Cold agglutination -Usually has to do with IgM bodies that cause RBCs to agglutinate and form irregular clusters of varying clusters -This causes an elevated MCH count and a lowered RBC count. -Can be fixed by warming up blood or prevented by keeping blood at 37 degrees Celsius Rouleaux -An alignment of RBCs which resembles a stack of coins -Can be artifact EDTA -Corrected by suspending cells in saline, aka saline replacement.
Outline the history of hematology
-In 1657 Kircher described worms in the blood -In 1674 Leeuwenhoek gave an account for RBC -In 1800's Bizzozero described platelets as petite plaques -In 1902 Wright developed the write stain and opened the world to visual examinations through a microscope.
• What is the rule of 3?
-RBC * 3= hgb -Hgb * 3= HCT
Given the number of cells observed per field and the magnification of the objective, apply formulas to estimate white blood cell (WBC) counts and platelet counts.
Absolute WBC= total WBC * relative count (%) PLT: Not an official method but used for QC - PLT estimate= (PLT counted/ number of fields) x 10,000
Given the relative reticulocyte count and RBC count, calculate the absolute reticulocyte count
Absolute= (retic % x RBC x 1000)/ 100
Correlate the age of a patient and the typical changes in CBC results compared to a normal adult CBC.
At birth RBC are around where they should be, but dip around 2 months. After 2 months, they slowly go back up to an adult level (4-5.5 depending on sex)
Describe the composition of blood
Blood is composed of plasma and cellular/formed elements. The "formed elements of blood contain RBC, WBC, and PLTs- making up 45% of the blood. Plasma makes up 55% of the blood and contains a liquid component that has water, ions, proteins, carbs, fats, hormones, vitamins, enzymes, antibodies, coagulation factors, and more. Within the formed elements, RBC make up 44% while WBC and PLTs make up 1%.
List the assays typically included in the complete blood count (CBC) and peripheral blood smear examination
CBC (complete blood count) -RBC, WBC, PLT, Hgb, HTC, RDW, MCV, MCH, MCHC, MPV, RET Peripheral blood smear examination -Used for overall quality, morphology of WBC's, RBC's, PLTs, and for a WBC differential
Classify CBC parameters based on whether they are measured, calculated, or derived.
Direct: RBC, WBC, Hgb Calculated: HCT, MCHC, MCH Derived: PLT, MPV, MCV, RDW Derived from size distribution of PLTs and RBCs
Follow the appropriate course of action to recognize and correct ethylenediaminetetraacetic acid-induced pseudothrombocytopenia and pseudoleukocytosis.
Fancy way of saying EDTA-induced pseudothrombocytopenia and pseudoleukocytosis - in-vitro sampling problem that occurs when EDTA causes clumping of PLTs which can mimic a low PLT count
Identify and discuss uses of hematology and hemostasis screening tests, including specimen requirements
Hematology uses multiple hemostasis screening test, such as: MPV (Mean platelet volume), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen assay, and D-dimer assay. The lab/heme department is especially focused on blood specimen integrity for coagulation labs because minor blood specimen defects render the specimen useless. Defects can be: clots, hemolysis, lipemia, plasma bilirubin, and short draws.
Define hemostasis (primary, secondary, and fibrinolysis) and the result of upset hemostatic process
Hemostasis is the process of forming a blood clot to stop blood loss. The primary stage consists of a platelet (PLT) plug being formed to stop the bleeding. The secondary stage of hemostasis is the formation of insoluble, cross-linked fibrin by coagulation factors, specifically Thrombin. Fibrin stabilizes the plug
Evaluate distribution of erythrocytes on stained smears, and describe how the distribution could affect the CBC results.
If the RBCs are too thick and covering each other, the machine will count it as one RBC which will cause low RBC and high WBC. Too thin will cause an inaccurate report
Describe the process of evaluating the peripheral blood smear.
Low Power Magnification 10x (sometimes 4x) -WBC: scans for abnormal or large cells/smudge cells -RBCs: scans for rouleaux and agglutination -PLTs: scans for clumps and satelitism 40x or 50x examination -Perform WBC estimate -Determine RBC critical area 100x Examination -WBC: evaluate morphology and preform 100-cell differential -RBC: Evaluate RBC morphology: size, shape, color, presence of inclusions -PLT: Perform PLT estimate and evaluate morphology: size and granularity
Define the terms MCV, MCH, MCHC, and RDW.
MCV: mean cell volume -Measures the size of RBC -Microcytic, normocytic, macrocytic MCH: Mean cell hemoglobin -Measures the amount of hemoglobin per 1 RBC MCHC: Mean cell hemoglobin concentration -The concentration of hgb relative to the amount of cell space it occupies -Normochromic or hypochromic (hyperchromic is very rare and generally is among spherocytes >36 but <37) RDW: RBC distribution width -Measures the variability of RBC sizes (anisocytosis)
Given the correct parameters, calculate the RBC indices, Hct and MCV.
MCV= (HCT/RBC) *10 HCT= (RBC * MCV) *10 MCH= (HGB/RBC) *10 MCHC= (HGB/HCT) *100
Given hematology testing and reference intervals, determine abnormal tests, associated reflex testing, and possible causes for abnormal result.
One example in hematology is when a PTT (Partial thromboplastin time) is abnormal, a PT (prothrombin time) is performed. In microbiology, when a urine analysis is positive for leukocytes and nitrates, a culture will be performed.
Define poikilocytosis and anisocytosis.
Poikilocytosis: variability in RBC SHAPE Anisocytosis: variability in RBC SIZE
Correlate polychromatophilia on a blood smear with other laboratory results of erythrocyte production and destruction
Polychromasia is a disorder where there is an abnormally high number of immature red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation. Bluish-gray color
Describe QA and QC processes related to hematology.
Quality assurance (QA) is the sum of all the actions taken in the laboratory to ensure that the information generated is correct. QA aims to prevent any lab errors and to focus on the processes used to test specimens. An example of this is checking pipettes, testing media, checking blood tubes for cracks, training personal accurately, using controls, cleaning, etc. QA is focused on prevention while QC is product oriented and focuses on how the measurement system can produce the same result over and over. This can be routine charts for maintenance, cleaning charts, control charts, etc.
What is the function of erythrocytes, leukocytes, plasma, and platelets?
RBC (erythrocytes) act as a transporter for O2 and CO2 and contain hemoglobin. WBC (leukocytes) act as the body's defense against foreign antigens. PLTs (thrombocytes) are necessary for hemostasis and clotting. Plasma acts as a transport medium for cell nutrients and metabolites
Describe hematology testing including reflex testing and the laboratory's role in designing reflex testing protocols and reference ranges
Reflex testing is follow-up testing due to the results of screening tests. The laboratory designs algorithms for tests that would create a follow-up test.
Detect abnormalities on peripheral blood smear examination, assess how they can alter cell count results (i.e., presence of nucleated erythrocytes or platelet satellitism), and recommend corrective action to ensure valid results.
Satellitism: when PLTs stick to neutrophils -Causes neutrophil count to lower, can be eliminated by dilution
Compare reference intervals for hemoglobin, hematocrit, erythrocytes, and leukocytes for infants, children, and adults
See other quizlet "reference intervals"
Classify erythrocytes morphologically based on erythrocyte indices.
Separate quizlet :)
Describe and identify specific poikilocytes and anisocytes (RBC morphology).
Separate quizlet :)
Identify the reference interval for each test and describe the variations in the CBC and Differential reference ranges based on age, ethnicity, and environmental factors
Separate quizlet for adult intervals. BUT generally there are physiologic differences, such as: -race, age, gender, and geographic location but there is also pathologic changes, such as: disease or injury
Define hematology
Study of the cellular components of blood
Three components of lab testing and errors with each component
The three components of lab testing are the pre-analytical stage, the analytical stage, and the post-analytical stage. During the pre-analytical stage, the patient is identified and prepped, the sample is collected and transported, and the sample is accepted or rejected. Many things can go wrong during this step, for example: patient misidentification, hemolyzed sample, clotted samples, order of draw not being followed, collected below IV-line, specimen not being kept at proper transport temperature, and more. The second stage, analyzing, is when the specimen is tested. This step can also have errors, such as performing the wrong test, contamination of sample during testing, using the wrong reagent, and more. The last step is post-analytical, which consists of reviewing the results, posting the results, monitoring turn-around time, and maintaining patient records. Errors during this step can consist of: not clearly reporting results that could cause misunderstanding, not keeping up with equipment maintenance, having a high turn-around time, and not bettering the practice based on customer satisfaction surveys.
List the typical units of measure for reporting the CBC parameters (ex. WBC, RBC, Hgb, Hct, reticulocyte count, etc.)
WBC: x10^3 RBC: x10^6 Hb: (g/dl) HCT: %
Explain causes of change in the steady state of blood components
a. Concerning WBC, an increase may be linked with infections, inflammation, cancer, leukemia. When WBC levels are decreased, it could be due to certain medications, autoimmune conditions, severe infections (HIV), and bone marrow failure. b. Concerning RBC, an increase could be due to dehydration, diarrhea, and burns. Decrease could be due to anemia. HCT and hgb mirrors these situations also. c. MCV (mean cell volume) and MCH (mean cell hemoglobin) could be increased with B12 and Folate deficiency but decreased with iron deficiency and thalassemia. d. MCHC (mean cell hemoglobin concentration) may be decreased if MCV is decreased and can only increase to a certain amount of Hgb that will fit in the cell. e. RDW (RBC distribution width) is increased if there is a mixed population of RBC f. Platelets will be increased or decreased with platelet production conditions. Decreased PLTs can cause a bleeding disorder because the body cannot produce clots. PLTs will be decreased with certain disorders, such as: Systemic lupus, anemia, hypersplenism (spleen takes too many out of circulation), Leukemia, and chemotherapy.
