Mean Corpuscular Hemoglobin (MCH) Calculator

Variables and formula

The MCH calculator determines the mean corpuscular haemoglobin value which represents the amount of haemoglobin located on erythrocytes (red blood cells).

It is a great indicator of oxygen circulation and is used in diagnosis of several types of anemia.

This is one of the RBC indices and is obtained by dividing the amount of hemoglobin in a blood sample by the amount of red blood cells and then multiplying the result by 10.

MCH in pg = (Hemoglobin in g/dL) / (RBC x 10¹²/L) x 10

Normal values for the above parameters can be found in the table below:

*The measurement unit for MCH is picogram. This is equivalent to 10-12 grams.

The other two RBC indices are Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin Concentration (MCHC).

As part of the complete blood count (CBC), the MCH determination does not differ from normal blood tests which involve venopunction.

The amount of discomfort at the pricking or stinging sensation differs from one person to another.

About MCH values

Elevated MCH values are characteristic of macrocytic red blood cells which carry more haemoglobin (past the 35 pg mark).

A high MCH indicates macrocytic anemia, which is caused by B12 or folic acid deficiencies. Similar to high MCV, high MCH is also indicative of alcoholism.

Decreased MCH values indicate hypochromic anemia which is characterized by microcytic erythrocytes (less Hb than the 27 pg mark). Low MCH levels are usually caused by:

■ Iron deficiency;

■ Microcytic anemia;

■ Blood loss;

■ Hemoglobinopathy (changes in the structure of Hb).

The order PLT/MCH ratio is used to differentiate between the two main causes of microcytic anemia:

■ iron deficiency anemia (IDA);

■ combined iron and vitamin B12 deficiency (IDA-B12).

Mean corpuscular hemoglobin levels have also proven accurate and cost effective in screening alpha-thalassemia-1 trait and beta-thalassemia traits in pregnant patients.

References

1. Williams WJ. Examination of the blood. In: Williams WJ, Beutler E, Erslev AJ, Lichtman MA, eds. Hematology, 3d ed. New York: McGraw-Hill, 1983;9–14.

2. 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.

3. Beyan C, Kaptan K, Beyan E, Turan M. The platelet count/mean corpuscular hemoglobin ratio distinguishes combined iron and vitamin B12 deficiency from uncomplicated iron deficiency. Int J Hematol. 2005; 81(4):301-3.

4. Pranpanus S, Sirichotiyakul S, Srisupundit K, Tongsong T. Sensitivity and specificity of mean corpuscular hemoglobin (MCH): for screening alpha-thalassemia-1 trait and beta-thalassemia trait. J Med Assoc Thai. 2009; 92(6):739-43.