Calculation of red cell indices

absolute values

1. CALCULATION OF RED CELL INDICES (ABSOLUTE VALUES) PRESENTED BY MISS TASMIA ZEB

2. CALCULATION OF RED CELL INDICES (ABSOLUTE VALUES) Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) are generally referred to as Red Cell Indices or Absolute Values. A recent addition is the calculation of RDW. These form the basis for the morphological classification of anaemias. Absolute values are best determined by automated haematology analysers but can be calculated from the following measured parameters: • Total red cell count (expressed as count x1012/L). • Packed cell volume (expressed as L/L) • Haemoglobin concentration (expressed as g/L)

3. MEAN CORPUSCULAR VOLUME (MCV) MEAN CORPUSCULAR VOLUME (MCV) or mean cell volume is the volume of one red cell expressed in femtoliters This can be calculated using following formula if PCV and the TRBC are known: MCV in femtoliters(fl)= Reference range Adult (both sexes): 80-96 fl MCV is increased in macrocytic anemia and decreased in microcytic anemia like thalassemia and iron deficency anemia

4. MEAN CORPUSCULAR HAEMOGLOBIN (MCH) MEAN CORPUSCULAR HAEMOGLOBIN (MCH) or mean cell hemoglobin is the average amount of hemoglobin present in a single red cell. it is expressed in picograms or uug This can be calculated by using following formula if Hb and TRBC are known: MCH in picograms= Hb level /TRBC ×10 Reference range Adults (both sexes): 27.0-32.0 pg In macrocytic anemias,there is high MCH because cells are larger and contain more hemoglobin .in microcytic anemia (unless spherocytic) MCH is low.

5. MEAN CORPUSCULAR HAEMOGLOBIN CONCENTRATION (MCHC) MEAN CORPUSCULAR HAEMOGLOBIN CONCENTRATION (MCHC) This expresses of concentration of hemoglobin per unit volume of red cells This can be calculated using the following formula if the Hb and PCV are known: MCHC IN g/dl=Hb/pcv ×100 Reference range Adults (both sexes): 32-36 g/dl MCHC is expressed in g/dl and low values are associated with iron deficiency of anemia. in macrocytic anemia ,the MCHC is normal or slightly reduced.

6. Note MCH is more reliable when obtained from an automated counter, as RBC count and Hb are more accurate. On the other hand, MCHC can be more reliable in a manual system as this is calculated by Hb and Hct and both of these can be measured accurately by manual method