Hemoglobin Test

A hemoglobin test measures the levels of hemoglobin in your blood. Hemoglobin is an iron-rich protein in your red blood cells. It carries oxygen from your lungs to the rest of your body.

Your cells need oxygen to grow, reproduce, and make energy for you to function. Your hemoglobin levels provide information about the health of your red blood cells. If your hemoglobin levels are abnormal, it may be a sign that you have a blood disorder.

Why this test is done

Your health care provider may order the test as part of a routine exam, or if you have:

• Symptoms of anemia, which include weakness, dizziness, and cold hands and feet
• A family history of thalassemia, sickle cell anemia, or other inherited blood disorder
• A diet low in iron and other minerals
• A long-term infection
• Excessive blood loss from an injury or surgical procedure

You may also need this test to monitor the treatment of anemia or the other health conditions that could affect your hemoglobin level.

How to prepare

You don't need any special preparation for a hemoglobin test. If your provider has ordered other blood tests, you may need to fast (not eat or drink) for several hours before the test. Your provider will let you know if there are any special instructions.

Sample type

Blood

Other names for this test

Hb, Hgb, H&H