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Mean Corpuscular Hemoglobin: Low & High MCH
Mean corpuscular hemoglobin (abbreviated as
MCH) is an estimate of the amount of hemoglobin in
an average red blood cell. Hemoglobin is a
substance in the blood that carries oxygen to the
cells in the body from the lungs.
Red blood cells help carry oxygen in the blood
because red blood cells contain hemoglobin.
HOW IS THE MEAN CORPUSCULAR
HEMOGLOBIN CALCULATED?
The MCH is calculated by multiplying the total amount of hemoglobin by 10 and
dividing that number by the total number of red blood cells.
FEATURED BOOK: Mosby's Diagnostic and Laboratory Test Reference
WHAT IS THE NORMAL LEVEL OF THE MEAN CORPUSCULAR HEMOGLOBIN?
The normal MCH level is between 26 and 33 picograms (one trillionth of a gram) of
hemoglobin per red blood cell. A gram is a very small unit of weight (you would need
453.359237 grams just to get one pound). This gives you an idea of how small a
picogram is. It is important to keep in mind that the ranges mentioned above will be
different depending on the machine used to do the blood test. Always use the normal
range printed on the lab report to decide what range is normal.
WHAT CAN CAUSE THE MEAN CORPUSCULAR HEMOGLOBIN
TO BE TOO HIGH?
Generally, if the MCH level is over 34, this is considered to be too
high. The main reason that the MCH level would be too high is
because of macrocytic anemia.
Macrocytic anemia is a blood disorder in which not enough red
blood cells are produced, but the ones that are present are large
(thus fitting more hemoglobin). Macrocytic anemia is often caused
by having too little vitamin B12 or folic acid (a type of vitamin) in
the body.
WHAT CAN CAUSE THE MEAN CORPUSCULAR HEMOGLOBIN TO BE TOO LOW?
Generally, if the MCH level is below 26, this is considered too low. The MCH level can be too low
because of blood loss over time, too little iron in the body, or microcytic anemia. Microcytic anemia is a
condition in which abnormally small red blood cells are present. Smaller red blood cells means that less
hemoglobin fits in each cell. Microcytic anemia is often caused by too little iron. As was mentioned
earlier, hemoglobin is substance present in red blood cells that help carry oxygen to cells in the body.
Hemoglobinopathy, which is a group of disorders characterized by changes in the structure of
hemoglobin, can also cause a low MCH level.
WHY IS IT CALLED MEAN CORPUSCULAR HEMOGLOBIN?
Another word for the average of something is the mean. The word "mean" comes from the Middle English
word "mene" meaning "in the middle." Corpuscular comes from the Latin word "corpusculum" meaning
"little body." In this case, the red blood cells are the little bodies. Hemoglobin is a substance in the blood
that carries oxygen to the cells in the body. Hemoglobin comes from the Greek word "haima" meaning
"blood," and the Latin word "globus" meaning "ball." Put the words together and you have "blood ball." In
sum, now you can see why the mean corpuscular hemoglobin means the average amount of hemoglobin
in each red blood cell.
