What is hemoglobin?
Hemoglobin is the protein in red blood cells that carries oxygen, combining it with oxygen in the lungs and releasing it into the tissues. It gives the cells and blood their red color. Hemoglobin is a marker for the total number of red cells in your blood sample.
To qualify for blood donation, you must have a hemoglobin of 12.5 g/dL or higher for females and 13.0 g/dL for males.