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hemoglobin(Hb) (he´mo-glo″bin) the main functional constituent of the erythrocyte, serving as the oxygen-carrying protein; it is a type of hemoprotein in which each molecule contains two pairs of polypeptide chains, the globins, each with an attached heme molecule that contains iron and a protoporphyrin molecule. The iron on a hemoglobin molecule can bind oxygen (see oxyhemoglobin), and hemoglobin is an efficient transport protein. Some hemoglobin compounds are seen in the blood in pathologic states such as carbon monoxide poisoning and methemoglobinemia. hemoglobin A1c
hemoglobin A with a glucose group attached to the amino terminal of the beta chain; it is made at a slow constant rate during
the 120-day life span of the erythrocyte. It accounts for 3 to 6 per cent of the total hemoglobin in a normal person and up
to 12 per cent in persons with diabetes mellitus. Increased levels correlate with glucose intolerance in diabetics; with good
diabetic control its level returns to normal range, so that periodic assays can be helpful in evaluating effective control
of diabetes. glycated hemoglobin
, glycosylated hemoglobin
any of various hemoglobins with glucose attached nonenzymatically; the most common one is hemoglobin A1c. The percentage of hemoglobin that is glycosylated can be assessed over a long period of time as a gauge of blood sugar control;
the normal range for a nondiabetic person is between 4 and 6 per cent. mean corpuscular hemoglobin(MCH)
the average hemoglobin content of an erythrocyte, conventionally expressed in picograms per red cell, obtained by multiplying the blood hemoglobin concentration (in g/dL)
by ten and dividing by the red cell count (in millions per mL): MCH = Hb/RBC.
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