Hemoglobin

This is the oxygen carrying compound of the red cells.
Hemoglobin can be measured chemically, and the amount of hemoglobin/L or 100 mL of blood can be used as an index of the oxygen carrying capacity of the blood. Total blood hemoglobin depends on the number of RBCs (the hemoglobin carriers), but also (to a much lower extent) on the amount of hemoglobin in each RBC. A low hemoglobin level indicates anemia .

Reference values

Hemoglobin reference values are most frequently quoted as 13.5-17.5 g/dL for males and 12.0-16.0 g/dL for females. Infants and children have considerably different hemoglobin values than do adults. The local range of reference must also be considered; for example, increase in altitude causes a physiologic increase in hemoglobin, such that the normal hemoglobin level in Denver will be higher than in Omaha.