Knowledge Check • The Blood Project

What does MCH stand for?

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Mean corpuscular hemoglobin

What does MCHC stand for?

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Mean corpuscular hemoglobin concentration

Match the parameter with the units:

MCHC

MCV

MCH

Picograms

Femtoliters

Grams per liter

Correct! Sorry, Incorrect.

What does the mean corpuscular hemoglobin correlate with (more than one answer may apply)?

a

Red cell size

b

Red cell count

c

Mean corpuscular hemoglobin concentration

d

Hematocrit

MCH tracks with MCV and MCHC. Assuming a constant MCHC, the MCH correlates with MCV. Assuming a constant MCV, the MCH correlates with the MCHC. With few exceptions (see next slide for an example), the MCH does not provide useful information that cannot be gleaned from the other red cell indices.

You join NASA as a medical researcher and are tasked with designing an experiment to study the effect of space travel on the hemoglobin/hematocrit and mean corpuscular volume (MCV). The space shuttle cannot accommodate an automated hematology analyzer, so you instruct the astronauts to draw blood during sequential weeks into EDTA-containing tubes, and store it on board at 4 degrees C. You plan to run the samples through a automated analyzer upon return to earth. However, red blood cells take on water during storage, so their size (the mean corpuscular volume [MCV]) artifactually increases while the shuttle is in orbit.

How do you control for this effect of storage on the MCV?

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You measure the MCH as a surrogate for the MCV. A rare example where the MCH is helpful!