RBC indices are calculated* parameters that are part of an automated blood count report. RBC indices have two primary uses:
- Assist with the differentiation of anemias
- Serve as quality control checks
RBC indices include:
- Mean cell (or corpuscular) volume (MCV)
- Mean cell hemoglobin (MCH)
- Mean cell hemoglobin concentration (MCHC)
These parameters identify characteristics of the red cells that are circulating at the time that the sample was collected. The table below summarizes the three parameters to include definition, reporting units, formulas for calculation of each parameter, and a sample calculation.
MCV refers to the average size of the RBCs constituting the sample. Should a mixture of cell populations be present, the sizes of the red cells will be averaged. Reporting units is femtoliters (fL). One femtoliter is 10-15 L. Reference interval for adults is typically 80 - 100 fL.
Mean cell hemoglobin (MCH) refers to the average weight of hemoglobin in the RBCs in the sample. Should a mixture of cell populations be present, the weights of the evaluated cells will be averaged. Reporting units is picograms (pg). One picogram is 10 -12 grams. The reference interval for adults is typically 26 - 32 pg.
Mean cell hemoglobin concentration (MCHC) refers to the average concentration of hemoglobin in the RBCs contained within the sample. Should a mixture of cell populations be present, the hemoglobin concentration within the evaluated cells will be averaged. Reporting units is g/dL. Reference interval for adults is typically 32 - 36 g/dL.
| Parameter | Definition
| Units | Formula
| Example
|
Mean cell volume (MCV)
| Average volume of the red blood cell (RBC)
| Femtoliters (fL) or 10-15Liter
|  |  |
Mean cell hemoglobin (MCH)
| Average weight of hemoglobin (Hb) in the RBC
| Picograms (pg) or 10-12 grams
|  |  |
Mean cell hemoglobin concentration (MCHC)
| Average concentration of Hb in the RBC volume
| Grams/deciliter (g/dL)
|  |  |
*Some hematology instruments measure MCV directly and derive hematocrit rather than calculating MCV from a measured hematocrit and red blood cell count.
