ANEMIAreduction of the total circulating red cell mass below normal limits.

RED CELL INDICES

Mean cell volume: the average volume of a red cell expressed in femtoliters (fL)

Mean cell hemoglobin: the average content (mass) of hemoglobin per red cell, expressed in picograms

Mean cell hemoglobin concentration: the average concentration of hemoglobin in a given volume of packed red cells, expressed in grams per deciliter

Red cell distribution width: the coefficient of variation of red cell volume

ADULT REFERENCE RANGES FOR RED CELLS

Measurement (units) Men WomenHemoglobin (gm/dL) 13.6–17.2 12.0–15.0

Hematocrit (%) 39–49 33–43

Red cell count (× 106/μL)

4.3–5.9 3.5–5.0

Reticulocyte count (%) 0.5–1.5

Mean cell volume (fL) 82–96

Mean cell hemoglobin (pg)

27–33

Mean cell hemoglobin concentration (gm/dL)

33–37

Red cell distribution width

11.5–14.5

CONDITIONS ASSOCIATED WITH DISCORDANCE BETWEEN HEMOGLOBIN CONCENTRATION AND RED CELL MASS

Increase in plasma volume relative to RBC mass (Hb disproportionately low)

Hydremia of pregnancy Congestive splenomegaly Recumbency (vs. upright) Decrease in plasma

volume relative to RBC mass (Hb high, normal, or low; but high relative to RBC mass)

Dehydration Protracted diarrhea

(especially in infants)

Peritoneal dialysis with hypertonic solutions

Diabetic acidosis Diabetes insipidus with

restricted fluid intake Burn patients Stress erythrocytosis,

spurious polycythemia Decrease in both plasma

volume and RBC mass (Hb normal, RBC mass low)

Acute blood loss Chronic disease

RECYCLING OLD CELLS

RBCs have 120-day life span Reticulo-endothelial system removes old and

damaged cells Hemoglobin is made of Fe++, porphyrin ring,

and globin chains Fe++ and globin chains (amino acids) are

recycled, but porphyrin ring is eliminated

CLASSIFICATIONS OF ANEMIA.

According to alterations in red cell morphology,

According to etiology

Terms commonly used in describing anemiaNormocytic, microcytic, or macrocytic

HB TEST

Reference ranges: Male 14.0 - 17.0 g% Female 12.0 - 15.0 g%

Cyanomethemoglobin method Drabkin’s reagent - ferricyanide Coulter Hemoglobinometer

HEMATOCRIT

Reference rangesMale 42 - 52%Female 36 - 46%

Packed cell volume

Modern instruments calculate Hct from RBC and average cell size

QUESTIONS TO ASK IN THE INITIAL EVALUATION OF ANEMIA