1. MLAB 1415- Hematology Keri Brophy-Martinez
Anemia
Part One

2. Anemia
Anemia is the inability of the blood to supply the tissue with adequate oxygen for proper metabolic function.
Clinically, anemia is defined as a decrease in the normal concentration of hemoglobin or erythrocytes.
Anemia is not a disease, but an expression of an underlying disorder or disease.

3. Development of Anemia Anemia occurs if:
Erythrocyte loss or destruction exceeds the maximum capacity of bone marrow erythrocyte production OR
Bone marrow erythrocyte production is impaired or abnormal

4. Causes of anemia Acute blood loss (hemorrhage)
Accelerated destruction of RBC’s (immune or non-immune)
Nutritional deficiency (iron, folate or B12)
Bone marrow replacement (e.g. cancer)
Infection
Toxicity
Hematopoietic stem cell arrest or damage
Hereditary or acquired defect

5. Anemia Classifications
Functional
Uses absolute and corrected retic count, RPI, and serum iron for classification
Types
Survival Defects(Increased Destruction)
Proliferation Defects(Decreased production)
Maturation Defects

6. Anemia Classifications
Morphologic
Uses erythrocyte indices (MCV) for classification
Types
Macrocytic, Normochromic
Causes: Folate or B12 deficiency, liver disease, alcoholism
Normocytic, Normochromic
Causes: bone marrow failure, hemolytic anemia, chronic renal failure, leukemia, metastatic malignancy
Microcytic,Hypochromic
Most common anemia
Causes: iron deficiency, sideroblastic anemia, thalassemia, chronic diseases

8. Diagnosis of anemia Clinical history
Physical signs such as pallor, fatigue, weakness and shortness of breath
Laboratory tests
CBC
Examination of the blood smear
Reticulocyte - measures effective erythropoiesis
Bone marrow examination
Iron studies - iron, total iron-binding capacity (TIBC), ferritin
Vitamin B12 and folate
Erythropoietin level

9. Laboratory Tests for Measurement of Anemia

10. Lab Tests Hemoglobin Reference values Hematocrit Reference values
Male: g/dl
Female: g/dl
Moderate anemia:
7-10 g/dl
Severe anemia:
<7 g/dl
Reference values
Male: %
Female: 36-46%

11. Parameters of the CBC (complete blood count)
Red Blood Count or RBC
Hemoglobin
Hematocrit
Note: the approximate relationship of the hemoglobin to the hematocrit is 1:3. This may vary with the cause of the anemia and the effect on the RBC indices, especially the MCV.
RBC indices
MCV - mean cell volume
Normal: fL (femtoliters)
Measured directly on automated cell counters
Used to classify RBCs as normocytic, microcytic or macrocytic
Indicates the average volume of the red cells
Calculation: Hct x 10
RBC

12. RBC Indices con’t MCH - mean cell hemoglobin weight
Normal: pg
A measurement of the hemoglobin content in RBC’s
Calculation: Hgb x 10
RBC
MCHC - mean cell hemoglobin concentration
Normal: %
Used to classify RBCs as normochromic, or hypochromic
A measure of the concentration of hemoglobin in the average RBC
Calculation: Hgb x 100
Hct

13. Parameters of the CBC (complete blood count)
RDW -Red Cell Distribution Width
Calculated index used to identify anisocytosis
Normal: %
Calculation: Standard deviation of MCV x100
Mean MCV

14. Reticulocyte Adult reference range: 0.5 - 2.5%
Useful in determining the response to the anemia and the potential of the bone marrow to manufacture RBC’s. Expressed as a percentage of the RBC’s.
When anemia is present, it is helpful to correct the retic using the patient’s hematocrit in order to assess appropriate bone marrow response
A supravital stain called New Methylene Blue is used to stain reticulocytes. On a Wright’s stained smear, reticulocytes appear as bluish red cells. The term used for retics on Wright’s stain is polychromasia.
Corrected retic% = retic % X Patient hct
Normal hct* based on age and sex
[*Normal female hct = 42%]
[*Normal male hct = 45%]

15. Reticulocyte maturation time in days RPI = corrected retic
Prematurely released retics remain in the blood and take from ½ to 1 ½ days longer to mature. This will cause even the “corrected” retic to be elevated, so a calculation must be performed to correct for this situation to obtain the reticulocyte production index (RPI). A maturation time table is used for this calculation.
Indicator of the adequacy of the bone marrow response in anemia
RPI>2: good bone marrow response
RPI<2: inadequate response
RPI = corrected retic
maturation time in days

16. Adult Reference Ranges
Red Blood Cells
Male: x 106 /µl
Female: x 106 /µl
Hemoglobin
Male: g/dl
Female: g/dl
Hematocrit
Male: %
Female: %
MCV fL
MCH
28-34 pg
MCHC
32-36 %
Reticulocyte %
RDW %

17. References
Harmening, D. M. (2009). Clinical Hematology and Fundamentals of Hemostasis. Philadelphia: F.A Davis.
McKenzie, S. B., & Williams, J. L. (2010). Clinical Laboratory Hematology . Upper Saddle River: Pearson Education, Inc.