Hematology (Pathology)

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HEMATOLOGY
OBJECTIVES OF CLASS
At the end of this class you will be able to:
Recognize various normal parameters dealing with RBC
Define anemia
Classify anemia
RBC
Size: range from 6-8.5 mm
Roughly same as that of the nucleus of a small lymphocyte on the dried film
Shape: biconcave
Central palor
Hemoglobin (Hb)
The Hb content is given in grams per deciliter.
Men :                    15.0 ± 2.0 g/l
Women:              13.5 ± 1.5 g/l
Child                     11-22 gm/dl
Hematocrit (Hct)
About 3 times the hemoglobin.
Normal values:
Men :                    0.45 ± 0.05 (l/l)
Women:                              0.41 ± 0.05 (l/l)
Clinical significance
Value below normal à anemia
Value above normal à polycythemia
RBC count
The number of RBC’s per unit volume.
Normal Values:
Men      :                              5.0 ± 0.5 × 1012/l
Women   :             4.3 ± 0.5 × 1012/l
Erythrocyte indices
Helpful in classifying RBC as to their size and Hb content.
Hb, Hct and RBC count are used to calculate the three indices:
    1. Mean Corpuscular Volume (MCV)
    2. Mean Corpuscular Hemoglobin (MCH)
    3. Mean Corpuscular Hemoglobin Concentration (MCHC)
Mean Corpuscular Volume (MCV)
Is the average volume of a red blood cell.
The unit is a femtoliter.
Normal range: 80-100 fL.
MCV= Hematocrit / RBC count
Used to classify RBC’s as
                Normocytic        : MCV =                80-100 fL
                Microcytic           : MCV =                <80 fL
                Macrocytic          : MCV =                >100 fL
Mean Corpuscular Hemoglobin
Concentration (MCHC)
Is the average concentration of Hb in grams in a deciliter of RBC.
Normal range = 32-36 g/dL
MCHC= Hb / Hct
Classifies the cells as
Normochromic          32-36
Hypochromic     <32
Hyperchromic   >36
Mean Corpuscular Hemoglobin (MCH)
Is the average weight (mass) of Hb per RBC.
The unit is a picogram.
Normal range - 29.5 ± 2.5 pg
MCH=Hb / RBC count
Clinical significance of erythrocyte indices
Values altered in anemias.
Indices used to classify anemias morphologically.
  1. Microcytic hypochromic anemia
  2. Macrocytic Normochromic anemia
  3. Normocytic normochromic anemia
Reticulocytes
Are immature, anuclear, larger red cells that contain free ribosomal RNA.
They spend a day in peripheral blood before becoming mature RBC.
Identification: Supravital stain (new methylene blue)
Reticulocyte count
Reticulocyte count: indicates degree of bone marrow activity.
(Normal= 0.4-2%)
Anemia
Anemia is defined as a reduction of the total circulating red cell mass below normal limits
Reduction in the oxygen carrying capacity of the blood
Characterized by reduced hemoglobin and reduced red cell mass
below the lower normal level for age and sex of individual. 
Classification of anemia
  1. According to morphology of RBC
MORPHOLOGICAL classification
2. According to etiology
ETIOLOGICAL classification
MORPHOLOGICAL CLASSIFICATION
Morphological classification
1. Normocytic- Normochromic
Acute blood loss
Chronic renal failure
2. Microcytic- Hypochromic
iron deficiency
thalessemia
3. Macrocytic- Normochromic
Vitamin B12 and folate deficiency
Alcoholic liver disease
Etiological classification
Anemia due to:
    1. Blood loss
    2. Increased rate of destruction (hemolytic anemias)
    3. Impaired red cell production
1. BLOOD LOSS:
Acute : trauma
Chronic: lesions of GIT, gynecological disturbances.
2. IMPAIRED RED CELL PRODUCTION:
Megaloblastic anemia (B12 and Folate)
Iron deficiency anemia
Anemia of chronic diseases
Aplastic anemia
Myelophthisic anemia (due to marrow infiltration)
Sideroblastic anemia
3. INCREASED RATE OF DESTRUCTION (HEMOLYTIC ANEMIAS)
A. Intrinsic abnormality of red cells
Hereditary spherocytosis
G6PD deficiency anemia
Thalessemia
Sickle cell anemia
Paroxysmal nocturnal hemoglobinuria
B. Extrinsic abnormality:
Immune hemolytic anemias
Autoimmune hemolytic anemia (AIHA)
Cold AIHA
Incompatible blood transfusion
Hemolytic disease of the newborn
Others:
Disseminated intravascular coagulation, Malaria etc.
  1. Hemoglobin
  2. Hematocrit
  3. RBC count
  4. Reticulocyte count
  5. Erythrocyte indices
  6. Blood smear examination
  7. Bone marrow examination
  8. Bilirubin
  9. Urine and stool for blood
Alteration in RBC morphology
Anisocytosis: term used to describe variation in the size of RBC (aniso = unequal)
Poikilocytosis: term used to describe variation in the shape of RBC (poikilo=various)
Anisopoikilocytosis: variation in size and shape of RBC.
Aniso-poikilocytosis
MACROCYTES
MACRO-OVALOCYTE
MICROCYTES
HYPOCHROMIC cells
Polychromatophils
Bone marrow examination
Important if other tests not conclusive.
Helps in definitive diagnosis.
Also important in diagnosis and management of hamatopoietic malignancy.
Two procedures:
    1. bone marrow aspirate (morphology)
    2. bone marrow biopsy (architecture and cellularity)
Bone marrow aspirate
Site: Post. Iliac crest, Sternum, Tibia
Instrument : Klima needle.
MICROSCOPIC EXAMINATION:
Cellularity
Erythropoiesis
Leucopoiesis
Megakaryopoiesis
Other cells
M:E ratio : normal: = 2-5:1
Iron stores
BM – aspirate (low power)
High power
Bone marrow biopsy:
Advantage:
                Architecture
                Cellularity
                In case of dry tap
                Imprint
Instrument: Jamshidi needle
Stain: Hematoxylin and eosin
Microscopic examination:

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