Manual Immature Reticulocyte Fraction: a reliable marker to assess post traumatic blood loss.

Abstract

Abstract. Hemorrhage is a common stress condition following acute trauma that needs prompt medical attention as it can be fatal. Traumatic haemorrhage be classified into three categories; mild, moderate and severe based on clinical manifestations and outcomes expected with each. However, some instances, clinical features may not reflect exact degree of blood loss due to other comorbid factors etc. Rapid marrow response to haemorrhage includes release of more immature red cells; reticulocytes and normoblasts depending on haemopoietic stimulus. Therefore, the presence of red cell precursors in peripheral blood is an expected marker following acute hemorrhage. Among reticulocyte parameters, Immature Reticulocyte Fraction (IRF) is widely used to indicate the erythropoietic activity of the bone marrow in stress conditions. Even though the manual reticulocyte count is performed in laboratories, calculation of manual IRF is not routinely practiced. Based on morphology, reticulocytes can be classified in to immature and mature sub types. Although automated method is available, it is costly to use. Therefore this study was performed to evaluate the relationship of manual IRF with degree of hemorrhage in acute trauma. In this analytical cross-sectional study, 38 blood samples of acute trauma patients admitted to emergency trauma care at a tertiary care hospital were analyzed. The IRF values were significantly higher in study subjects with severe hemorrhage than mild and moderate. When the time duration from trauma to admission was considered, subjects with clinically severe hemorrhage showed high IRF values within one hour. Appearance of the most immature (stage I) reticulocytes were noted after two hours of trauma in study subjects. Therefore, this study supports us ability of manual IRF in objective assessment of early marrow response to hemorrhage thus assessment of severity of acute trauma. Thus the manual IRF in peripheral blood can be considered an important, reliable and cheap laboratory indicator in acute trauma care in the diagnosis and management acute blood loss.