Intra-day and inter-day biological variations of peripheral blood lymphocytes

Abstract

BackgroundThe proportion and absolute numbers of lymphocyte subsets are important indices that reflect the immunological status of the body. Few studies on biological variations of absolute lymphocyte subset counts and no study in Asian population are currently available. Furthermore, there have been few reports on the biological variation of these indices in the short term. MethodsAt 8:00AM, 12:00PM, and 4:00PM on days 1, 3, and 5, venous blood was collected from 20 healthy volunteers. All participants maintained their normal lifestyles. The percent and absolute lymphocyte subset counts were measured using single -platform method. ResultsIntraday and interday biological variations for the absolute and percent counts of lymphocyte subsets were relatively constant. The intra-individual coefficient of variation (CVI) and inter-individual coefficient of variation (CVG) were similar to those in previous studies. Biological variations in the percent and absolute counts for the CD3+CD4−CD8−, CD3+CD4+CD8+, and CD3+CD16+CD56+ subsets were relatively high. ConclusionsThese observations are clinically valuable. Investigation on the CVI and CVG may allow us to determine the utility of traditional population based reference ranges. Documentation of the reference change values may be used as objective delta-check values in quality management and decide whether the change that occur in an individual's serial results before the change is significant. The present study also enriched the database regarding the biological variations of lymphocyte subsets in Asian population.