The red cell indices — MCV, MCH, and MCHC — turn three raw complete blood count numbers into a size-and-color profile of the average red blood cell. That profile is the starting point for classifying anemia and narrowing the differential diagnosis before any further workup.

How the indices are calculated

MCV = (Hematocrit ÷ RBC count) × 10, giving the average red cell volume in femtoliters. MCH = (Hemoglobin ÷ RBC count) × 10, giving the average hemoglobin mass per cell in picograms. MCHC = (Hemoglobin ÷ Hematocrit) × 100, giving the hemoglobin concentration within the average cell in g/dL. All three use values from the same complete blood count.

MCV and MCH tend to move together since both use RBC count in the denominator, but MCHC is independent — it only reflects hemoglobin relative to hematocrit, which is why it is the axis used for the hypochromic/normochromic classification instead of MCV.

Reading the classification

MCV under 80 fL is microcytic, 80–100 fL is normocytic, and over 100 fL is macrocytic. MCHC under 32 g/dL is hypochromic and 32–36 g/dL is normochromic; values over 36 g/dL are uncommon and usually reflect spherocytosis or a lab artifact rather than a distinct anemia type. Crossing these two axes — for example "microcytic, hypochromic" — gives the classic pattern hematology teaching uses to organize the differential for anemia.

RDW, the red cell distribution width, adds a third dimension: an elevated RDW signals a mixed population of cell sizes (anisocytosis), which helps distinguish, for example, iron deficiency anemia (typically high RDW) from thalassemia trait (typically normal RDW) even when both present as microcytic and hypochromic.

Limits and edge cases

This calculator is a screening and classification tool, not a diagnosis. The same MCV/MCHC pattern can arise from several different underlying causes, and the Differential Hints tab lists the common teaching differential, not an exhaustive or ranked list. A single CBC can also be affected by recent transfusion, acute blood loss, or lab variability, so a borderline or unexpected result is worth repeating before drawing conclusions. Confirming the underlying cause of an abnormal pattern generally requires further workup — iron studies, a peripheral smear, vitamin B12/folate levels, or hemoglobin electrophoresis — interpreted by a clinician alongside the full clinical picture.