The mean corpuscular hemoglobin concentration (MCHC) is the average hemoglobin concentration in a given volume of packed red blood cells. It is expressed as grams per deciliter. It is reported as part of a standard complete blood count.
MCHC may be calculated from the MCV (Mean cell volume) and the MCH (Mean Corpuscular Hemoglobin) or from the hemoglobin (HGB) and hematocrit (Hct) values by using the following formula:
MCHС (g/dL) = hemoglobin (in g/dL) × 100 / Hematocrit (in %) (1)
or
MCHС (g/dL) = MCH (in pg) × 100 / MCV (in fL) (2)
Example:
If the hemoglobin concentration is 15 g/dL and the Hct is 45%:
MCHС (g/dL) = 15 g/dL × 100 / 45 % = 33.3 g/dL
Reference ranges for blood tests are 32 to 36 g/dL, or between 19.9 and 22.3 mmol/L. It is thus a mass or molar concentration.
Values below 32 g/dL indicate hypochromasia. An MCHC above 40 g/dL would indicate malfunctioning of the instrument. An impossibly high MCHC (>40 g/dL) also could indicate the presence of cold agglutinins in the specimen. An MCHC of 37 g/dL is near the upper limits for hemoglobin solubility and the physiologic upper limits for the MCHC. The MCHC typically increases only in spherocytosis. In other anemias it is decreased or normal. In true hypochromic anemias, the hemoglobin concentration is reduced, and values as low as 20 to 25 g/dL may be seen.
Still, many instances measure MCHC in percentage (%), as if it were a mass fraction (mHb / mRBC). Numerically, however, the MCHC in g/dL and the mass fraction of hemoglobin in red blood cells in % are identical, assuming a RBC density of 1g/mL and negligible hemoglobin in plasma.