Background: In order to establish suitable reference intervals (RIs) of serum cytokeratin-19 fragment (Cyfra211) and neuron specific enolase (NSE) for the healthy Chinese population in Chengdu, China, an indirect method was developed using the data from the people presented for routine health check-up.
Methods: All results for 4,988 healthy persons serum cytokeratin-19 fragment and 3,293 healthy persons neuron specific enolase were collected in our laboratory information system between January 2016 and December 2018. Outliers were identified and excluded using the stem-and-leaf and box plot methods. Mann-Whitney U test was used to observe the difference between sexes. Spearman’s rank correlation analysis was used to evaluate the correlation between serum results and age. The RIs were defined by nonparametric 95th percentile interval.
Results: After statistical analysis the indirect RIs were 0.0 - 3.70 ng/mL (Cyfra211) and 0 - 17.26 ng/mL (NSE) in males and 0.0 - 3.35 ng/mL (Cyfra211) and 0.0 - 16.29 ng/mL (NSE) in females. Cyfra211 and NSE levels in males and females had no correlation with age. Therefore, there was no need to establish RIs according to age group. RIs of Cyfra211 and NSE were verified and passed the verification in the end.
Conclusions: Using health check-up persons’ laboratory data values is a relatively easy and cheap method of establishing laboratory specific references. This method deserves to be promoted and applied by other clinical laboratories.