Comparison of the sensitivity of various reticulocyte indices in the diagnosis of hemolytic anemia

Reticulocyte shows the bone marrow response to anemia. Reticulocytes remain in the bone marrow for 2 days before mature erythrocytes and in the peripheral blood for 1 day. The duration of reticulocytes in the peripheral blood is prolonged in severe anemias. In order for the reticulocyte count to be used as a measure of bone marrow production, a correction must be made for the duration of in the circulation. Therefore, the corrected reticulocyte ratio and reticulocyte production index are calculated. Reticulocytosis is a characteristic finding in hemolytic anemias. In our study, it was aimed to compare the sensitivity of different reticulocyte parameters in patients with hemolytic anemia and to find the most helpful parameter in diagnosis. The study was retrospective. 70 patients with hemolytic anemia who were admitted to Hacettepe University Faculty of Medicine Department of Hematology were included. A control group of 50 age- and sex-matched individuals was established. The absolute reticulocyte count, reticulocyte ratio, hemoglobin-corrected reticulocyte ratio, hematocrit-corrected reticulocyte ratio and reticulocyte production index were calculated. All these parameters were compared for the diagnosis of hemolytic anemia.. Age and gender distribution were similar in the patient and control groups. All reticulocyte parameters were significantly higher in the patient group than control group. When the literature-cited and commonly accepted cut-off values were used hemoglobin- and hematocrit-corrected reticulocyte ratios showed the best predictivities (98.5% sensitivity and 12% 1-specificity for 2% cut-off). However the other reticulocyte indices (absolute count and reticulocyte production index) did not perform well. ROC analysis was undertaken in order to find the best (100% sensitivity and the highest specificity) cut-off values for diagnosis of hemolytic anemia in our cohort. vii In conclusion, literature-defined cut-off values of the reticulocyte indices other than hemoglobin- and hematocrit-corrected reticulocyte ratios (absolute reticulocyte count and reticulocyte production index) are not acceptably predictive for the diagnosis of hemolytic anemia. Keywords: reticulocyte, hemolytic anemia, corrected reticulocyte ratio