Hematology

• RBC Count: The number of RBCs per unit volume is measured directly and given in millions per microliter.
• Mean Corpuscular Volume (MCV): The MCV is measured directly. The unit is a femtoliter (fL), or it can be given as cubic millimeters (mm3). The MCV measures the size of RBCs and is the most important index for classification of anemias into "macrocytic" with higher-than-normal MCV and "microcytic" with low MCV.
• Hemoglobin (Hgb): The Hgb content is measured directly and given in grams per deciliter (g/dL). This value, along with Hct, provides the most useful measure of the oxygen carrying capacity of the blood.
• Hematocrit (Hct) in % = (RBC count in millions X MCV) ÷ 10: The Hct is the packed cell volume and is a calculated value and provides a measure of the amount of oxygen carrying capacity in relation to blood volume.
• Mean Corpuscular Hemoglobin (MCH) in pg = (Hgb X 10) ÷ RBC count in millions: The MCH is calculated and gives the average mass of Hgb in an individual RBC; the unit is a picogram (pg).
• Mean Corpuscular Hemoglobin Concentration (MCHC) in g/dL = (Hgb X 100) ÷ Hct: The MCHC is calculated and provides a measure of the concentration of Hgb in the cells in g/dL.
• Red Cell Distribution Width (RDW): The RDW is calculated to provide a measure of the anisocytosis, or variation in size of the RBCs. RDW = (Standard deviation of MCV/mean MCV) × 100. Normal range11.5–14.5% has suspicion of thalassemia trait & high often indicates IDA
• Mentzer index = (MCV/RBC count). < 13 may represent thalassemia trait & >13 often indicates IDA