Reticulocyte Hb expression reported by the Mindray BC6800 Plus analyzer for the detection of iron deficiency in patient blood management

Background: The essential elements of patient blood management (PBM) are based on preventing and correcting risk factors that could lead to the need for transfusion. Perioperative iron deficiency and anemia are common in patients presenting for surgery. The reticulocyte hemoglobin (Hb) content has been recommended for studying erythropoiesis status because it can correctly evaluate iron deficiency erythropoiesis and identify suboptimal hemoglobinization in the early stages. We evaluated the diagnostic performance of the reticulocyte Hb expression (RHe), a proprietary parameter reported by the Mindray BC6800 Plus analyzer in detecting iron-restricted erythropoiesis in the context of the preoperative evaluation of patients undergoing arthroplasty. Methods: Patients were recruited in the course of their preoperative controls. Mann-Whitney U test was applied to detect statistical deviations between the groups, patients with normal iron stores and those with latent iron deficiency (LID) and thus iron-restricted erythropoiesis; P value <0.05 was considered significant. Receiver operating characteristic (ROC) curve analysis was utilized to illustrate the performance of RHe to detect iron-restricted erythropoiesis; s-ferritin <30 µg/L was the gold standard. Results: A total of 7.3% patients suffered from anemia. In the group of non-anemic patients (n=342), 31.4% had s-ferritin values below the threshold of iron-restricted erythropoiesis, 30 µg/L; in this group, 81% of them had RHe <30.0 pg. Median RHe in the LID group was 26.1 pg, statistically different from the group with) normal iron stores, 30.9 pg (P<0.001). RHe had the best performance area under the curve (AUC) 0.825 (95% CI: 0.747–0.895) at cut-off 30.0 pg, with a sensitivity of 82.8% and specificity of 70.1%; Hb, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and red cell distribution width (RDW) rendered 0.539, 0.734, 0.728 and 0.774, respectively. Conclusions: Preoperative iron deficiency is independently associated with increased mortality and prolonged hospital stay after surgery. LID screening, not only anemia, is important in the context of a comprehensive PBM. RHe can reflect the negative balance in iron supply for erythropoiesis; measuring RHe as a routine preoperative parameter could thus be a valuable, relatively inexpensive option for a strategic adoption of PBM in surgical practice, contributing to reduce cost and time and to improve logistics and the outcomes of patients undergoing surgery.