Anemia - Diagnosis

Determining Causes of Iron Deficiency. When iron deficiency anemia is diagnosed, the next step is to determine what causes the iron deficiency itself.

Dietary iron deficiency is most common in children and infants. It is rare in adults.
Heavy menstrual or abnormal uterine bleeding is usually the cause of iron deficiencies in young women. Increased need for iron during pregnancy is also a common cause in this population.
If internal bleeding is suspected as the cause, the gastrointestinal tract is usually the first suspect as the source. A diagnosis in such cases can be 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. In such cases, stool tests for this hidden (occult) blood are required. Additional tests may then be needed 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. Although endoscopy is not always performed in iron deficient patients if there are no signs of GI bleeding, one study suggested that this procedure could reveal other causes, including some cancers, in many patients.

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If the patient's diet suggests low iron intake and other causes cannot be established using inexpensive or noninvasive techniques, then the patient may simply be given a monthly trial of iron supplements. If the patient fails to respond, further evaluation is needed.

Diagnosing Anemia of Chronic Disease (ACD)

Usually anemia of chronic disease is recognized during the management of the primary disease and, if the anemia is mild, additional diagnostic tests are rarely needed. The following are typical findings in ACD:

The blood cells are normal looking.
Blood tests may typically show low levels of iron in the blood, but ferritin levels are normal or even high. (Low levels of ferritin, a protein that binds to iron, indicate iron deficiency.)

Diagnosing Vitamin B-Related Anemias

Doctors need a multi-step diagnostic procedure for determining vitamin B deficiencies and the anemias that cause or are caused by them. Doctors may arrive at a diagnosis of vitamin B12 or folic acid deficiencies from different routes:

They may diagnose deficiencies after detecting megaloblastic anemia from abnormal blood tests.
They may suspect vitamin deficiencies first from symptoms and history and then look for anemia.

Diagnosing Megaloblastic Anemia. Very large oval red blood cells indicate megaloblastic anemia. Abnormally shaped neutrophils (certain white blood cells) may also be present. Bone marrow aspiration may need to be performed if the disease is strongly suspected but the diagnosis is not clear.