Mean Corpuscular Hemoglobin Concentration (MCHC) Calculator

Variables and formula

The average concentration of haemoglobin in a red blood cell sample, measured in g/dL, is known as the mean corpuscular haemoglobin concentration and is reported as part of the three RBC indices, determined in the complete blood count (CBC), along: Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH).

The main role of haemoglobin is in the circulation of oxygen from the lungs to the tissues and cells of the body.

A recent study has tested the prognostic value of hematological parameters and serum ion levels.

MCHC was found to be an independent prognostic factor for both short and long term outcomes of acute myocardial infarction (AMI) in patients admitted to the ICU.

MCHC is obtained by multiplying the amount of hemoglobin found in the blood by 100 and then dividing the number to the hematocrit value, which is the cellular amount in the blood, obtained through blood centrifugation.

MCHC in g/dL = (Hemoglobin in g/dL) / (Hematocrit %) x 100

The table below contains the normal range values (according to the American Association for Clinical Chemistry) for the parameters used in the calculation:

*Other sources use a wider range: 32 to 36 g/dL and some regional variations may occur due to the variability in results provided by different testing machines used in automated analysis.

Instead of g/dL, the MCHC may be expressed in mmol/L with normal values between 19.9 and 22.3.

The sample of blood for the test is collected by venipuncture. The procedure is simple: a needle is gently inserted in one of the arm veins and the blood content is collected in a tube.

Minor discomfort is felt in the form of a small prick or stinging. The result time depends on the laboratory.

Abnormally low MCHC

Values below 28 g/dL are considered in the low spectrum and may indicate one of the following:

■ Blood loss;

■ Iron deficiency;

■ Hypochromic anemia.

The paler the color of the erythrocytes, the lower the HB concentration in them, thus the MCHC.

Hypochromic anemia may be caused by:

■ Problems absorbing iron;

■ Diffuse internal bleeding;

■ Malignancy;

■ Other conditions.

As discussed in the previous section, low MCHC values are also associated with increased risk of adverse outcome in ICU patients diagnosed with AMI.

Most nutritional deficiencies can be corrected through a mineral rich diet and/or supplement intake.

For example iron deficiency can also be corrected through oral or IV iron supplementation.

Elevated MCHC

Values over 36 g/dL are considered high and may indicate spherocytosis. This is a condition in which erythrocytes present an abnormal quantity of Hb.

The RBCs get the name spherocytes because of their new sphere-shapes form rather than the normal bi-concave disk shape.

Other indications of hyperchromic erythrocytes include:

■ Vitamin B12 deficiency;

■ Folic acid deficiency.

Lipemia leads to false increases in Hb levels that are also reflected in the MCHC value which is dependent on Hb.

In hemolysis, due to the fewer intact RBCs and a decrease in the calculated haemoglobin, the MCHC value may again be falsely increased.

Agglutination or excess EDTA during testing are also known to determine false elevated levels.

References

1. Briggs C, Bain BJ. Basic Haematological Techniques. Bain BJ, Bates I, Laffan M, Lewis SM. Dacie and Lewis Practical Haematology. 11th ed. Philadelphia, PA: Churchill Livingstone/Elsevier; 2012. chap 3.

2. The McGill Physiology Virtual Lab (2016) Blood cell indices - MCV and MCHC.

3. Clark MR. Mean corpuscular hemoglobin concentration and cell deformability. Ann N Y Acad Sci. 1989; 565:284-94.

4. Huang YL, Hu ZD. Lower mean corpuscular hemoglobin concentration is associated with poorer outcomes in intensive care unit admitted patients with acute myocardial infarction. Ann Transl Med. 2016; 4(10): 190.