Manual immature reticulocyte fraction; a surrogate marker to assess post traumatic blood loss

Introduction: Erythropoietic response following chemotherapy and stem cell transplant is assessed by reticulocytosis and immature reticulocyte fraction (IRF). They are not used to assess erythropoiesis following acute haemorrhage even though it is known to cause reticulocytosis. This study was performed to evaluate the use of IRF as a marker of degree of post-traumatic haemorrhage.

Methods: A cross sectional descriptive study was performed using routine anticoagulated blood samples collected from patients admitted with acute traumatic haemorrhage to an emergency treatment unit. Differential and total reticulocyte counts were performed manually using standard techniques with bright field microscopy. The data on severity of blood loss were extracted from clinical records.

Results: There were total of 38 patients. Mean IRF of patients with mild (n = 14), moderate (n = 19) and severe (n = 05) haemorrhage were 1.86 ± 1.0%, 3.26 ± 1.8% and 10.2 ± 3.6% respectively. Mean manual IRF of group with severe haemorrhage was significantly higher than those of all the others (p = 0.000). The mean manual IRF of moderate haemorrhage group was significantly higher than that of mild group (p = 0.01). Manual IRF and severity of haemorrhage were significantly positively correlated (r = 0.71, p < 0.01, n = 38). Immature reticulocytes of stage I was observed only in patients with severe haemorrhage.

Conclusion: The manual IRF can be used as a reliable marker of severity of post-traumatic acute haemorrhage.