Table of Contents
Total Iron Binding Capacity. Total iron binding capacity (TIBC) measures the level of transferrin in the blood. Transferrin is a protein that carries iron in the blood. TIBC calculates how much or how little the transferrin in the body is carrying iron. A higher than normal TIBC is a sign of iron-deficiency anemia. A lower than normal level may indicate anemia of chronic disease, sickle cell, pernicious anemia, or hemolytic anemia.
Reticulocyte Count. Reticulocytes are young red blood cells, and their count reflects the rate of red blood cell production. The upper normal limit is about 100,000/mL. A low count, when bleeding isn't the cause, suggests production problems in the bone marrow. An abnormally high count indicates that red blood cells are being destroyed in high numbers and indicates hemolytic anemia. Recent research suggests that the reticulocyte hemoglobin content (CHr) test may be more accurate than a standard hemoglobin test for detecting iron deficiency in infants.
Vitamin Deficiencies. The doctor may order tests for vitamin B12 and folate levels. The Schilling test is used to determine whether the body absorbs vitamin B12 normally.
Other Diagnostic Tests
If internal bleeding is suspected as the cause of anemia, the gastrointestinal tract is usually the first possible source. A diagnosis in these cases can often be made if the patient has noticed blood in the stools, which can be black and tarry or red-streaked. Often, however, bleeding may be present but not visible. If so, the patient needs stool tests for this hidden (occult) blood. The patient may need additional tests to diagnose the precipitating condition. Endoscopy, in which a fiber optic tube is used to view into the gastrointestinal tract, is helpful in many patients, particularly when the source of bleeding is unclear. A colonoscopy may also be recommended to rule out colorectal cancer.
If the patient's diet suggests low iron intake and other causes cannot be established using inexpensive or noninvasive techniques, the patient may simply be given a monthly trial of iron supplements. If the patient fails to respond, further evaluation is needed.
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Review Date: 01/13/2011
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School; Physician, Massachusetts General Hospital.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
