The Role of IRF (Immature Reticulocyte Fraction) in Pancytopenia

Background: Pancytopenia is an important entity worldwide but with varying patterns in clinical presentations. Bone marrow aspiration and biopsy are considered as primary investigation to evaluate and diagnose the causes of pancytopenia. But before doing a bone marrow aspiration or biopsy, a note on the newer reticulocyte indices given by automated cell counters other than reticulocyte percent and absolute reticulocyte count helps us to get a picture about the marrow erythropoietic activity which also bypasses the inter-observer variability. These newer reticulocyte indices are the Immature Reticulocyte Fraction (IRF), Reticulocyte Hemoglobin Content (CHr or Ret-He), difference between the reticulocyte and erythrocyte hemoglobin content (Delta-He). IRF was initially introduced to monitor the hematopoietic treatment in cases of childhood pancytopenia due to cancer chemotherapy. We attempted to emphasize the importance of Immature Reticulocyte Fraction (IRF) over other reticulocyte indices in diagnosis of pancytopenia and assessment of marrow response to therapy.

Methods: In this study patient’s history were taken. Then EDTA mixed blood examined by Automated Cell Counters (Sysmex XT-4000i) and subsequently bone marrow examination has been done to confirm the etiology. Results were calculated statistically.

Results: We found that values of IRF were also significant in the diagnoses of Megaloblastic Anaemia, Aplastic Anaemia, early Marrow Recovery from suppression, Hemolytic Disease and Chronic Diseases.

Conclusion: It is hypothesized that IRF is an index of acceleration and the absolute reticulocyte count is a quantitative measurement of the effectiveness of erythropoiesis. So after initiation of treatment, repeated observation of both IRF and Reticulocyte Count may be helpful to observe the effectiveness of therapy.