What relevance have MCH, MCV, MCHC re... - Pernicious Anaemi...

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What relevance have MCH, MCV, MCHC results have in possible B12 deficiency ?


I had some FBC tests done recently and the above plus Serum alkaline phosphatase were considered 'abnormal'. No treatment but combined with a low B12 serum test I wondered if there was a connection? Since then taking 1000mcg cyanacobalim pills plus 1200ug B12 spray hoping this will help. Better add I possibly have Hashimotos so this could all be due to thyroid not B12. Ten minutes with a GP just isn't long enough to ask all my questions so hope someone here can help. Thanks. j

4 Replies

MCV is a measure of the size of your red blood cells (Mean Cell Volume). A large MCV means macrocytic (large cell) anaemia. The most common causes of macrocytic anaemia are B12 and/or folate deficiencies. Small cells (low MCV) is caused most often by iron deficiency anaemia.

MCH is Mean Cell Haemaglobin. If you have large cells then they tend to have a lot of haemaglobin in them. So you tend to get high MCH with macrocytic anaemia.

MCHC is the Mean Cell Haemaglobin Concentration. Low MCHC is common with iron deficiency anaemia. High MCHC is rare and can be due to a coupleof things. But B12 and folate don't have any effect on MCHC.

Alkaline phosphatase can be raised by lots of things. Mine goes up if I drink a lot a day or two before the test.

jib70 in reply to fbirder

Thank you. So much easier to understand with your explanation..

jib70 in reply to fbirder

Sorry but another question regarding RBC results. Are high haemoglobin + high haematocrit separate problems or also relevant to high MCV and high MCH ?

fbirder in reply to jib70

Haemaglobin and haematocrit are different, but related.

When you spin blood down it separates into two fractions - the red cells and the plasma. The haematocrit value is the percentage of the blood that is the red cells. So a haematocrit of 0.43 would be 43% red cells, by volume.

Obviously, if you have a high haematocrit (and, therefore a lot of red cells) and the red cells have the normal amount of haemaglobin in them, then you will have high haemaglobin.

If you have a normal amount of red cells, but a high MCV, then the total volume of red cells will be large - a high haematocrit.

If you have a normal number of red cells, but a high MCH, then you will have high haemaglobin.

You may be getting the impression that all of these different numbers are inter-related. You'd be right.

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