Class of 2008 Abstract / Objectives: To examine the utilization of the various laboratory tests in diagnosing iron deficiency anemia and determine the proportion of patients receiving unnecessary iron supplementation. Methods: Included in the descriptive study were 126 adult patients with a diagnosis of iron-deficiency anemia determined by ICD9 codes at the University Medical Center (UMC) in Tucson, AZ. Demographic and clinical characteristics were collected by chart review and analyzed by calculating means, standard deviation, and range for patient’s age, iron dose, and lab values. The study also examined the percentage of each lab value (serum iron, transferrin, transferrin saturation, serum ferritin, and/or hemoglobin/hematocrit) used to diagnosis iron deficiency anemia and the percentage of patients found below common references ranges for each serum iron laboratory test were calculated. Results: The average age of the iron deficiency patient was 55 with an average daily elemental iron dose of 108.1 mg with a standard deviation of 50.0. The majority of the laboratory tests were utilized over 50% of the time, with the exception of transferrin (49.6%), transferrin saturation (44.8%), and ferritin (46.4%). The laboratory test with results below the reference range the least percentage of the time was ferritin at 13.8%. The hematocrit (95.1%), hemoglobin (93.6%), serum iron (92.6%), and transferrin saturation (91.1 %) were below the reference range in a high proportion of the patients. Conclusions: It appears that physicians in a hospital setting are not obtaining or utilizing the correct iron laboratory tests in the diagnosis of iron deficiency anemia, resulting in unnecessary iron supplementation.