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

Updated: Nov 26, 2019
  • Author: Joseph E Maakaron, MD; Chief Editor: Emmanuel C Besa, MD  more...
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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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