Iron deficiency anemia (IDA) is one of the most common forms of anemia with up to 80% of the world population suffering from it. Current widely used methods to determine IDA are hematology assay and transferrin saturation (TSAT). These methods have limitations such as they required two different specimens and could be affected by inflammation. Novel parameters such as reticulocyte hemoglobin (RET-He) could be used to measure iron reserve in bone marrow, whereas erythropoiesis is judged by immature reticulocyte fraction (IRF). Both parameters could be measured using one blood specimen. The aim of this study is to analyze the correlation between RET-He, IRF and TSAT in patients with IDA.