Application of Time Series Analysis to Serial Blood Neutrophil Counts in Normal Individuals and Patients Receiving Cyclophosphamide

摘要

Summary.For periods of time ranging from 1 to 3 mth white blood cell and differential counts were made daily on eight normal volunteers and two patients receiving cyclophosphamide. The patients tended to have lower mean neutrophil (PMN) counts than the volunteers; moreover, there was a corresponding decrease in the variability of the counts around the means.The PMN counts appear to follow a lognormal distribution which would arise if the mechanism stabilizing the PMN counts adjusts the number of circulating cells in a multiplicative manner.Periodogram analysis of the log PMN counts showed evidence of regular periodic variation in only one of the subjects, a patient undergoing treatment with cyclophosphamide. The sequences of daily log PMN counts appeared to represent first‐order autoregressions with an average serial correlation coefficient of 0.125. These findings indicate that a typical series of daily PMN counts does not show cyclic variatio