How are red blood cell (RBC) cellular indices calculated?

Updated: Oct 08, 2018
  • Author: Joseph E Maakaron, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Presently, RBC cellular indices are computer calculated and automatically placed on laboratory reports. The formulae for calculating these values follow (reference ranges are in parentheses). RBC is per million cells. •MCV = Hct × 10/RBC (84-96 fL) •Mean corpuscular Hb (MCH) = Hb × 10/RBC (26-36 pg) •Mean corpuscular Hb concentration (MCHC) = Hb × 10/Hct (32-36%) A rapid method of determining whether cellular indices are normocytic and normochromic is to multiply the RBC and Hb by 3. The RBC multiplied by 3 should equal the Hb, and the Hb multiplied by 3 should equal the Hct. Deviation from the calculated values suggests microcytosis, macrocytosis, or hypochromia versus the presence of spherocytes (MCHC >36).


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