Mean corpuscular hemoglobin concentration

hemoglobin

The mean corpuscular hemoglobin concentration, or MCHC, is a measure of the concentration of hemoglobin in a given volume of packed red blood cell. It is reported as part of a standard complete blood count.

It is calculated by dividing the hemoglobin by the hematocrit. Reference ranges for blood tests are 32 to 36 g/dl,^[1] or between 19 ^[2]-20^[2] to 22^[2] mmol/L.

Interpretation

It is diminished ("hypochromic") in microcytic anemias, and normal ("normochromic") in macrocytic anemias (due to larger cell size, though the hemoglobin amount or MCH is high, the concentration remains normal). MCHC is elevated in hereditary spherocytosis.

This count is used to give a rough guide to what shade of red, RBC will be. (paler=lower than the standard)

Complications with cold agglutinin

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 agglutinin. This means that when their blood gets colder than 37°C it starts to clump together. As a result, the analyzer may incorrectly report a low number of very dense red blood cells for blood samples in which agglutination has occurred.

This problem is 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.This is the most sensitive test for iron deficiency anemia.

Worked example

See also

• Red blood cell indices
  • Mean corpuscular volume
  • Mean corpuscular hemoglobin

References

1. ^ http://www.nlm.nih.gov/medlineplus/ency/article/003648.htm
2. ^ ^{a b c} Derived from mass concentration, using molar mass of 64,458 g/mol (Van Beekvelt MC, Colier WN, Wevers RA, Van Engelen BG (2001). "Performance of near-infrared spectroscopy in measuring local O2 consumption and blood flow in skeletal muscle". J Appl Physiol 90 (2): 511–519. PMID 11160049. ). 1 g/dL = 0.6206 mmol/L

External links

• FP Notebook
• Cornell
• Medline

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