Mean Corpuscular Hemoglobin (MCH) Calculator

How does this mean corpuscular hemoglobin (MCH) calculator work?

This health tool computes the average weight of hemoglobin in the tested red blood cell population. As part of the standard blood count CBC, this offers information on the amount of Hb in the erythrocytes which is very important for the oxygen circulation in the blood.

MCH, which is the acronym for Mean Corpuscular Hemoglobin, is one of the three RBC indices. The other two are Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin Concentration (MCHC).

It is obtained by dividing the amount of hemoglobin in the sample at the amount of red blood cells and then multiplying the amount by 10. The measurement unit for MCH is picogram, which is equivalent to 10^-12 grams.

Normal values for the parameters involved in the MCH calculator:

The MCH blood test does not differ from any taking of blood sample and involves venopunction. A sensation of pricking or stinging is felt and the amount of discomfort is minor but differs from person to person.

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

Elevated MCH

Macrocytic RBCs are large and have a higher concentration of hemoglobin in them. MCH is considered in the high spectrum when it goes past 35 pg.

Macrocytic anemia is caused by B12 or folic acid deficiencies. As with MCV, high MCHs is indicative of alcoholism.

Low MCH

This is characteristic of hypochromic anemias with microcytic erythrocytes with lower levels of hemoglobin in them. MCH levels below 26 pg are considered in the low spectrum and are usually caused by:

■ Blood loss;

■ Iron deficiency;

■ Microcytic anemia;

■ Hemoglobinopathy (changes in the structure of Hb).

Other considerations on MCH levels

MCH levels in the PLT/MCH ratio can help in the differentiation of microcytic anemia due to pure iron deficiency anemia (IDA) from anemia caused by the combined deficiencies of vitamin B(12) and iron (IDA-B12).

Hematologic parameters results have been correlated in a study of 240 apparently healthy infants and was found that MCH values have predictive value on further iron deficiency status.

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

Example of a calculation

Question: Given a patient with hemoglobin 12.5 g/dL and red blood cell count 4.1 x10¹²/L, what is their MCH?

Answer: MCH in pg = 12.5/4.1 x 10 = 30.48 pg (rounded to 30.5 pg).

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. (2005) The platelet count/mean corpuscular hemoglobin ratio distinguishes combined iron and vitamin B12 deficiency from uncomplicated iron deficiency. Int J Hematol; 81(4):301-3.

4) Knight GJ, Heese Hde V, Dempster WS, Kirsten G. (1983) Diagnosis of iron deficiency: mean corpuscular hemoglobin (MCH) as a predictor of iron deficiency in infants. Pediatr Res; 17(2):168-70.

5) Vajpayee N, Graham SS, Bem S. Basic Examination of Blood and Bone Marrow. McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd. Elsevier/Saunders: Philadelphia, PA; 2011. 30.

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