Development of a Prognostic Score Using the Complete Blood Cell Count for Survival Prediction in Unselected Critically Ill Patients

Objective. The purpose of this study was to develop a new prognostic scoring system for critically ill patients using the simple complete blood cell count (CBC). Methods. CBC measurements in samples from 306 patients in an intensive care unit were conducted with automated analyzers, including levels of neutrophils, lymphocytes, erythrocytes, hemoglobin, and platelets. The time of sampling and the time of death were recorded. Z values were calculated according to the measured values, reference mean values, and standard deviations. The prognostic score was equivalent to the median of the Z value of each of the measured parameters. Results. There was a significant correlation between survival time and neutrophil, lymphocyte, and platelet levels (P < 0.05). Prognostic scores were calculated from the Z value of these three parameters. Survival times decreased as the prognostic score increased. Conclusions. This study suggests that a model that uses levels of neutrophils, lymphocytes, and platelets is potentially useful in the objective evaluation of survival time or disease severity in unselected critically ill patients.