A-252 Laboratory Prediction of Early Neutrophil and Platelet Engraftment Using Advanced Hematology Analyzer Indices in Hematopoietic Stem Cell Transplantation

Abstract

Accurate prediction of engraftment after hematopoietic stem cell transplantation (HSCT) is vital for patient care. Conventional complete blood count (CBC) parameters such as absolute neutrophil count (ANC) and platelet count often lag behind true marrow recovery and may miss early engraftment, delaying timely clinical decisions. This study evaluated whether advanced research-use-only (RUO) hematology analyzer parameters — including reticulocyte, platelet, and WBC scatter measures — could offer practical, earlier engraftment prediction compared to standard counts. This prospective study included 11 patients (10 autologous, 1 allogeneic HSCT) at a single tertiary care center. A total of 231 daily CBC samples were analysed over the peri-transplant period (Day –10 to +30). Advanced analyzer parameters assessed included immature reticulocyte fraction (IRF), immature platelet fraction (IPF), scatter indices (e.g., NE-SFL, LY-X), and related RUO measures. Patient trends were visualized using Spaghetti plots aligned to engraftment days. Receiver Operating Characteristic (ROC) analysis assessed each parameter’s performance for predicting engraftment within the next three days. Area under curves (AUCs), 95% confidence intervals, and p-values were calculated using the Hanley & McNeil method. The median neutrophil engraftment day was Day +14 (range: D+10–D+25) and median platelet engraftment day was Day +19 (range: D+11–D+30). For neutrophil engraftment, no advanced RBC or platelet parameters showed significant early predictive ability (e.g., IRF AUC = 0.44, 95% CI 0.30–0.58, p = 0.389; IPF AUC = 0.39). In contrast, advanced white blood cell (WBC) scatter indices demonstrated robust performance: NE-SFL (AUC = 0.79, 95% CI 0.67–0.91, p < 0.001) and LY-X (AUC = 0.72, 95% CI 0.59–0.85, p = 0.001). These parameters discriminated engraftment status up to three days in advance. For platelet engraftment, advanced platelet and RBC parameters showed significant early predictive value. IPF (%) (AUC = 0.72, p = 0.001), IRF (%) (AUC = 0.71, 95% CI 0.58–0.84, p = 0.002), and P-LCR (%) (AUC = 0.70, 95% CI 0.57–0.83, p = 0.003) demonstrated upward trends starting 3–5 days before platelet engraftment. Selected advanced hematology analyzer parameters, particularly NE-SFL and LY-X, demonstrated significant early predictive utility for neutrophil engraftment, while IPF (%), IRF (%), and P-LCR (%) provided robust early prediction of platelet engraftment up to 3–5 days before counts normalized. These novel indices could complement standard counts, providing clinicians with actionable insight into marrow recovery during HSCT follow-up.