Using the hemoglobin content of reticulocytes (RET-He) to evaluate anemia in patients with cancer.

Evaluation of anemia, particularly iron deficiency, in patients with cancer is difficult. This study examined using the hemoglobin content of reticulocytes (RET-He) to rule out iron deficiency, as defined by serum iron studies (transferrin saturation <20%, serum iron <40 μg/dL, and ferritin <100 ng/mL), in an unselected cancer patient population. Patients were entered into the study based on the existence of concurrent laboratory test requests for CBC and serum iron studies. Using a threshold of 32 pg/cell, RET-He ruled out iron deficiency with a negative predictive value (NPV) of 98.5% and 100%, respectively, in the study population (n = 209) and in a subpopulation of patients with low reticulocyte counts (n = 19). In comparison, the NPV of traditional CBC parameters (hemoglobin, <11 g/dL; mean corpuscular volume, <80 fL) was only 88.5%. These results support the use of RET-He in the evaluation of iron deficiency in a cancer care setting.