Mean corpuscular hemoglobin concentration

The mean corpuscular hemoglobin concentration, or MCHC, is a measure of the concentration hemoglobin in a red blood cell. It is reported as part of a standard complete blood count. It is diminished in microcytic anemias, and increased in macrocytic anemias.

Because of the way automated analysers count blood cells, a very high MCHC (greater than about 370 g/L) may indicate the blood is from someone with a cold agglutination problem. This means that when their blood gets colder than 37°C it starts to clump together. This makes the machine think there are a low number of very dense red blood cells.

This is problem usually picked up by the laboratory before the result is reported. The blood is warmed until the cells separate from each other, and quickly put through the machine while still warm.