Abstract:

Objective To establish the reference interval of serum cytokeratin 19 fragment（CYFRA21-1） for local population,and to preliminarily investigate the factors for the level of CYFRA21-1. Methods A total of 8 199 healthy subjects were enrolled. Serum CYFRA21-1 and serum creatinine（SCr） levels were determined,and the estimated glomerular filtration rate（eGFR） was calculated. Non-parametric method was used to determine the upper limit of the reference interval by taking the unilateral 95th percentile（P₉₅）. The influence factors of sex,age and eGFR on CYFRA21-1 were analyzed. Results The Dixon method was used to exclude 7 outliers from the 8 199 subjects,and a total of 8 192 subjects were enrolled. Serum CYFRA21-1 level in males was higher than that in females（P<0.001）. There was statistical significance in CYFRA21-1 levels in different age groups（P<0.001）. The P₉₅ of serum CYFRA21-1 levels in males and females increased with age,especially in ≥60 years old groups. Non-parametric method was used to determine the reference intervals,which were 0-3.37 ng/mL for <60 years old,0-4.17 ng/mL for 60-69 years old,0-5.67 ng/mL for ≥70 years old. Spearman rank correlation analysis showed that serum CYFRA21-1 levels were positively correlated with age（r=0.213,P<0.001）,and they were negatively correlated with eGFR（r=-0.247,P<0.001）. The eGFR was negatively correlated with age（r=-0.612,P<0.001）. Quantile regression analysis showed that age（tau=0.95,β=0.02,P<0.001）,sex（tau=0.95,β=-0.24,P<0.001） and eGFR（tau=0.95,β=-0.01,P<0.001） were influence factors of CYFRA21-1 level. Conclusions The CYFRA21-1 reference interval in Wuhan has been established. Sex,age and eGFR are the influencing factors for serum CYFRA21-1 level.

Key words: Cytokeratin 19 fragment, Reference interval, Estimated glomerular filtration rate