1. Chapter 41
Hematology

2. Hematologic Tests Second most common type of tests performed in POL
Cellular components of blood affected by changes in organs or tissues of body

3. Hematologic Tests Hemoglobin Hematocrit WBC count
Differential WBC count
RBC count
RBC indices
Platelet count
Erythrocyte sedimentation rate (ESR)
Prothrombin time (PT)

4. Hematologic Tests
Tests provide valuable information for diagnosis, evaluating patient’s progress, regulating further treatment

5. Hematologic Tests Complete blood count Hemoglobin determination
Hematocrit determination
RBC count (and indices)
WBC count (and differential)
Platelet count

6. Hematologic Tests Complete blood count
Performed by manual testing procedures or automated hematology analyzer
Results recorded in patient’s medical record
Accurate and timely documentation important

7. Hemoglobin and Hematocrit Tests
Major component of RBC
Carrier of oxygen and carbon dioxide in body
85% of dry weight of RBC
Synthesis of heme requires iron
Adult man requires 0.5 mg/day of iron
Menstruating woman requires 2 mg/day of iron

8. Hemoglobin and Hematocrit Tests
Carries 95% of oxygen to cells
Carries away 27% of carbon dioxide to lungs to be expelled
Acts as blood buffer

9. Hemoglobin and Hematocrit Tests
Frequent hemoglobin disease is anemia
Measured in POL using automated device (HemoCue)
Reference values vary according to both age and sex
(See Procedure 41-1: Hemoglobin Determination Using a CLIA Waived Hemoglobin Analyzer)

10. Hemoglobin and Hematocrit Tests
Packed RBC volume is ratio of volume of packed RBCs to that of whole blood specimen
Cellular components of blood sample separate into layers when centrifuged at high speeds
WBCs
RBCs
Plasma
(See Procedure 41-2: Microhematocrit Determination)

11. Hemoglobin and Hematocrit Tests
Microhematocrit
Centrifuge
Packed cell column showing separation of cellular components >>
[FIGURES 41-5 and 41-6]

12. White and Red Blood Cell Counts
White blood cells and differential
WBCs travel to tissues of body to find and destroy pathogens
Abscess: localized accumulation of pus
Antibiotics are useful
Normal values for WBCs vary with age

13. Leukocyte Identification Guide
[FIGURE 41-7]

14. White and Red Blood Cell Counts
White blood cells and differential
Granulocytes: contain granules within their cytoplasm
Neutrophils
Basophils
Eosinophils
Leukocyte identified by contents of cytoplasm and shape of their nuclei
Agranulocytes: do not contain granules

15. White and Red Blood Cell Counts
White blood cells and differential
Specialized protection methods
Phagocytosis
Detoxification
Inflammation
Immune response

16. Red Blood Cells
Erythrocytes carry oxygen to body’s cells and bring back carbon dioxide
Formed in bone marrow
Varying sizes; round or slightly oval shape
Contains hemoglobin

17. Platelets Platelets (thrombocytes)
140,000 to 400,000 per microliter of blood
Have no nuclei
Involved in clotting of blood (coagulation)

18. Erythrocyte Indices Mean corpuscular (cell) volume (MCV)
Mean corpuscular hemoglobin (MCH)
Mean corpuscular hemoglobin concentration (MCHC)
Calculations that provide information about size of RBCs and hemoglobin content

19. Erythrocyte Indices
Blood parameters: RBC count, hematocrit, hemoglobin
Important in diagnosis or classification and treatment of different types of anemia

20. Erythrocyte Indices Using erythrocyte indices to diagnose
MCH and MCV increased in megaloblastic anemias
MCH and MCV increased in acute blood loss anemia, chronic hemolytic anemias, aplastic anemias, hypothyroidism, liver disease
MCH and MCV decreased in hypochromic and microcytic anemias and hyperthyroidism

21. Erythrocyte Indices Using erythrocyte indices to diagnose
MCHC increased in hereditary spherocytosis
MCHC normal in macrocytosis
MCHC decreased in iron deficiency anemia

22. Erythrocyte Sedimentation Rate
Measures rate at which RBCs fall toward bottom when placed in vertical tube >>
[FIGURE 41-8]

23. Erythrocyte Sedimentation Rate
ERS or “sed rate”
Used in diagnosis and treatment of many diseases
Inexpensive
Accurate
Easy test to perform
(See Procedure 41-3: Erythrocyte Sedimentation Rate)

24. Erythrocyte Sedimentation Rate
Wintrobe method
EDTA venous blood sample mixed
Blood transferred with Pasteur pipette to Wintrobe tube
No air bubbles
Place tube vertically in rack to stand for 60 minutes
Read number of millimeters red cells settled
Normal values for Wintrobe method of ESR

25. Erythrocyte Sedimentation Rate
Westergren method
Mix blood sample with 3.8% sodium citrate solution before filling tube
Normal values for Westergren method of ESR
Sediplast ESR system

26. Erythrocyte Sedimentation Rate
Guidelines for Wintrobe and Westergren ESR procedures to measure accurate results
Erythrocytes forming rouleaux >>
[FIGURE 41-10]

27. Erythrocyte Sedimentation Rate
Using the ESR to screen
ESRs increased in infections, acute stress, inflammatory diseases, tissue destruction, other conditions that lead to increase in plasma fibrinogen
Increased with menstruation, pregnancy, lupus, malignant neoplasms, multiple myeloma
With anemia, increases to severity of condition
Decreased in polycythemia, spherocytosis, sickle cell anemia

28. C-Reactive Proteins CRP level rise and drop is quicker than ESR
Better inflammation indicator than ESR
Helps in determining systemic inflammatory conditions
CRP made by liver
hsCRP used in conjunction with lipid profile and cardiac risk assessment

29. Coagulation Studies Prothrombin time (PT)
“Protime”
Measures time it takes patient’s blood to clot
Normal blood clots in seconds
International normalized ratio (INR)
Can be universally applied
(See Procedure 41-4: Prothrombin Time (Using CLIA Waived ProTime Analyzer))

30. Automated Hematology Advantages over manual methods:
Faster
Less expensive
Simple to operate
Accurate
Instruments can be calibrated and lend themselves to control testing; most equipped with printers

31. Automated Hematology
Can calculate part or all of RBC indices and print results
Can be connected to other computers in medical facility

32. Automated Hematology Turn on machine and perform control testing
Always follow manufacturer’s instructions
[FIGURE 41-10A]