Hemoglobin Hemoglobin Hemoglobin is an iron-protein compound in red blood cells that gives blood its red color. Its most important function is to carry oxygen from your lungs to the rest of your body. Hemoglobin is vital to life, and must remain at a healthy level in your body for your organs to function properly. If your hemoglobin level is low, it may mean that you are anemic.
Mild anemia has no symptoms.
Iron deficiency is the most common cause of anemia, but low levels of vitamins, kidney disease, and other illnesses are other common causes. If your hemoglobin level is high, it may mean that your body is not getting enough oxygen. A high hemoglobin can also be caused by some forms of cancer.