Abstract: Objective To assess biological variation of 23 routine laboratory tests from 100 healthy subjects for 5 consecutive years. Methods One hundred healthy study participants were enrolled from a tertiary hospital and fasting blood samples were collected once a year for 5 consecutive years and analyzed for 23 routine laboratory tests, including white blood cell counting (WBC), red blood cell counting (RBC), hemoglobin (HGB), Hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count (PLT), total bilirubin (TBIL), total protein (TP), albumin (ALB), Alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione transdermal enzyme (GGT), alkaline phosphatase (ALP), uric acid (URIC), urea (UREA), creatinine (CREA), glucose (GLU), triglyceride (TG), total cholesterol (CH), high density lipoprotein cholesterol (HDL) and Low density lipoprotein cholesterol (LDL), using a Hematology analyzer or biochemical analyzer. The data were subject to within-subject biological variation (CVI) and between-subjects biological variation (CVG) analysis. Results We found that CVI varied from 1.26% to 26.42%. Of these CVI, those of TBIL, ALT, GGT and TG were displayed above 20% while those of RBC, HGB, HCT, MCV, MCH, MCHC, TP and ALB were less than 5%. For CVG, there were more significantly different among these parameters. The estimates of CVG were obtained from 2.49% for MCHC to 52.98% for GGT. Of 23 parametres, CVG of TBIL (30.25%), ALT (37.72%), TG (39.70%) and GGT (52.98%) were above 30%, whereas those of MCHC, MCV and MCH were less than 5%, 2.49%, 3.71% and 3.73%, respectively. Most CVI and CVG estimates appear to be higher than those previously published in the online 2014 Westgard updated database. However, a few CVI and CVG estimates were superior to those online, such as CVI for RBC, MCH and PLT and CVG for MCV, MCH, PLT, ALT, ALP, CH, HDL and LDL. Conclousions Most biological variation estimates in this study were similar with the online database in Westgard website except a few of parametres. And our study made up for the lack of long-term biological variation in the database.

Key words: Biological variation, Routine, Quality goal