Doctors diagnose the cause of anemia, or low hemoglobin count, through several methods: reviewing medical histories, a physical exam and using the results of tests, says the National Heart, Lung and Blood Institute. Anemia often causes no major symptoms, so the condition is diagnosed during check-ups or tests for other conditions or diseases.
Physicians review both patient and family medical history when investigating anemia, in order to confirm symptoms. They also take into account any recent illnesses that may have led to the condition and any family history that may make the patient prone to it, according to the NHLBI. A physical exam allows the physician an opportunity to search for possible causes through examinations of heart and lung functions, and to conduct an investigation of any possible sources of blood loss. Blood tests allow a more specific diagnosis of the type of anemia from which a patient is suffering, and the tests reveal the severity of the condition.
The primary test to diagnose anemia is a complete blood count, reports the NHLBI. This test checks for levels of hemoglobin, an iron-rich protein in the blood responsible for carrying oxygen. The test also measures how much space red blood cells take up in the blood. Low counts on both are a sign of anemia.