Transcript Anemia
MLAB 1415- Hematology
Keri Brophy-Martinez
Anemia
Part One
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.
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
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
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
Anemia Classifications
Morphologic
Uses erythrocyte indices (MCV) for classification
Types
Macrocytic, Normochromic
Normocytic, Normochromic
Causes: Folate or B12 deficiency, liver disease, alcoholism
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
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
Laboratory Tests for
Measurement of Anemia
Lab Tests
Hemoglobin
Reference values
Moderate anemia:
Male: 14-17.4 g/dl
Female: 12-16 g/dl
7-10 g/dl
Severe anemia:
<7 g/dl
Hematocrit
Reference values
Male: 42-52%
Female: 36-46%
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:80-100 fL (femtoliters)
Derived from RBC histogram OR calculate
Used to classify RBCs as normocytic, microcytic or macrocytic
Indicates the average volume of the red cells
Calculation:
Hct x 10
RBC
RBC Indices con’t
MCH
- mean cell hemoglobin weight
Normal: 28-34 pg
A measurement of the hemoglobin content in RBC’s
Calculation:
Hgb x 10
RBC
MCHC - mean cell hemoglobin concentration
Normal: 32-36 %
Used to classify RBCs as normochromic, or hypochromic
A measure of the concentration of hemoglobin in the average RBC
Calculation:
Hgb x 100
Hct
Parameters of the CBC
(complete blood count)
RDW -Red Cell Distribution Width
Calculated index used to identify anisocytosis
Normal: 11.5-14.5%
Calculation: Standard deviation of MCV x100
Mean MCV
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%]
Reticulocyte
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
Adult Reference Ranges
Red Blood Cells
Male: 4.5-5.5 x 106 /µl
Female: 4.0-5.0 x 106 /µl
Hemoglobin
Male: 14-17.4 g/dl
Female: 12-16 g/dl
Hematocrit
Male: 42-52%
Female: 36-46%
MCV
80-100 fL
MCH
28-34 pg
MCHC
32-36 %
Reticulocyte
0.5-2.5%
RDW
11.5-14.5%
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.