Immature reticulocyte fraction is an early predictor of bone marrow recovery post chemotherapy in patients with acute leukemia.

OBJECTIVE To establish the benefits of immature reticulocyte fraction (IRF) measurement using an automated hematology cells analyzer over absolute neutrophil count (ANC) in predicting bone marrow recovery post induction chemotherapy. METHODS A prospective observational study was carried out in the Departments of Pathology, Medicine, and Pediatrics, Universiti Kebangsaan Malaysia, Medical Center (UKMMC), Kuala Lumpur, Malaysia during a period of 19 months from April 2009 to December 2010 to assess the bone marrow recovery in patients with acute leukemia. A total of 22 patients in remission induction phases were enrolled in this study. The blood specimens were collected from day zero after chemotherapy, and every 3 days until patients recovered hematologically. All blood samples were measured for ANC and IRF using an automated hematology analyzer (Beckman-Coulter LH750). RESULTS The percentage of patients showing IRF recovery earlier than ANC recovery was 63.6% (14 out of 22 patients). There was a significant difference in the mean number of days for IRF recovery as compared with ANC recovery (14.05 and 17.18 days), p=0.005. CONCLUSION This study proved that IRF was more useful in predicting bone marrow recovery in a patient with acute leukemia post induction chemotherapy compared with ANC. The IRF is not affected by infection, is easily measured, and inexpensive; thus, it is a reliable parameter to evaluate bone marrow reconstitution.