Download MLAB 1315- Hematology Fall 2007 Keri Brophy

MLAB 1415- Hematology
Keri Brophy-Martinez
Anemia
Part One
Anemia
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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
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Anemia occurs if:
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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
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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
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Morphologic
 Uses erythrocyte indices (MCV) for classification
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Types
 Macrocytic, Normochromic
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Normocytic, Normochromic
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Causes: Folate or B12 deficiency, liver disease, alcoholism
Causes: bone marrow failure, hemolytic anemia, chronic renal failure,
leukemia, metastatic malignancy
Microcytic,Hypochromic
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Most common anemia
Causes: iron deficiency, sideroblastic anemia, thalassemia, chronic
diseases
Diagnosis of anemia
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Clinical history
Physical signs such as pallor, fatigue, weakness and
shortness of breath
Laboratory tests
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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
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Reference values
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Moderate anemia:
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Male: 14-17.4 g/dl
Female: 12-16 g/dl
7-10 g/dl
Severe anemia:
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<7 g/dl
Hematocrit
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Reference values
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Male: 42-52%
Female: 36-46%
Parameters of the CBC (complete blood count)
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Red Blood Count or RBC
Hemoglobin
Hematocrit
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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
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MCV - mean cell volume
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Normal:80-100 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
RBC Indices con’t
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MCH
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- 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
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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)
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RDW -Red Cell Distribution Width
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Calculated index used to identify anisocytosis
Normal: 11.5-14.5%
Calculation: Standard deviation of MCV x100
Mean MCV
Reticulocyte
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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
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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
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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
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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.