There are 2 methods of expressing hemoglobin in SI Units. One is simple, while the second is more useful chemically but may be associated with some confusion.
The simplest method of expressing hemoglobin in SI Units is as g/L. Converting a hemoglobin g/dL to g/L involves multiplying the value by 10.
The second method of SI Unit expression is as mmol/L. The reported conversion factor from g/dL to mmol/L are:
(1) 0.6206 (Jordan; Kratz)
(2) 0.155 (Young, 1998; Wallach)
Hemoglobin is composed of 4 globin (2 alpha and 2 beta) molecules. Each globin chain carries 1 heme molecule, capable of carrying 1 molecule of oxygen. Each molecule of hemoglobin can carry 4 molecules of oxygen, so 1 mole of hemoglobin can carry 4 moles of oxygen.
Molecular weight of hemoglobin: 64, 500
Molecular weight of each globin chain: 16,100
If a molecular weight of 64,500 is used, then the conversion factor from g/dL to mmol/L is 0.155.
If a molecular weight of 16,100 is used (1 mole of globin chain, or 1 mole of oxygen carrying capacity), then the conversion factor from g/dL to mmol/L is 0.6206.
To read more or access our algorithms and calculators, please log in or register.