Diagnosis

To diagnose iron deficiency anemia, your doctor may run tests to look for:

• Red blood cell size and color. With iron deficiency anemia, red blood cells are smaller and paler in color than normal.
• Hematocrit. This is the percentage of your blood volume made up by red blood cells. Normal levels are generally between 35.5 and 44.9 percent for adult women and 38.3 to 48.6 percent for adult men. These values may change depending on your age.
• Hemoglobin. Lower than normal hemoglobin levels indicate anemia. The normal hemoglobin range is generally defined as 13.2 to 16.6 grams (g) of hemoglobin per deciliter (dL) of blood for men and 11.6 to 15. g/dL for women.
• Ferritin. This protein helps store iron in your body, and a low level of ferritin usually indicates a low level of stored iron.

Additional diagnostic tests

If your bloodwork indicates iron deficiency anemia, your doctor may order additional tests to identify an underlying cause, such as:

• Endoscopy. Doctors often check for bleeding from a hiatal hernia, an ulcer or the stomach with the aid of endoscopy. In this procedure, a thin, lighted tube equipped with a video camera is passed down your throat to your stomach. This allows your doctor to view the tube that runs from your mouth to your stomach (esophagus) and your stomach to look for sources of bleeding.
• Colonoscopy. To rule out lower intestinal sources of bleeding, your doctor may recommend a procedure called a colonoscopy. A thin, flexible tube equipped with a video camera is inserted into the rectum and guided to your colon. You're usually sedated during this test. A colonoscopy allows your doctor to view inside some or all of your colon and rectum to look for internal bleeding.
• Ultrasound. Women may also have a pelvic ultrasound to look for the cause of excess menstrual bleeding, such as uterine fibroids.

Your doctor may order these or other tests after a trial period of treatment with iron supplementation.