Establishment of reference interval for the tumour marker serum CYFRA 21-1 in healthy Chinese Han ethnic adults

<p><b>Background:</b> Our aim was to establish the reference interval (RI) for serum CYFRA 21-1 in healthy Chinese Han ethnic adults, since there has been no report about it.</p> <p><b>Methods:</b> After screening, 9954 healthy Chinese Han adults (age range 18–95 years) were recruited, including 6639 (66.7%) males and 3315 (33.3%) females. Electrochemiluminescence immunoassay was used to measure serum CYFRA21-1. The RI was defined by nonparametric 95% percentile interval.</p> <p><b>Results:</b> The distribution for serum CYFRA21-1 level was non-Gaussian. The RI for healthy Chinese Han adults calculated by nonparametric method was 0–4.47 ng/ml in this study, higher than that recommended by Roche Diagnostics GmbH (≤3.3 ng/ml). The reference values were higher in males than females before 50 years of age, although the difference was hardly seen after 50 years of age. The reference value increased with age in both males and females. Of slight difference, the increase of male reference value was obvious at 60–69 and more than 80 years of age, while that of female obvious at 50–69 and more than 80 years of age.</p> <p><b>Conclusions:</b> We establish the RI for serum CYFRA21-1 in healthy Chinese Han population, which is higher than that recommended by Roche Diagnostics GmbH. Furthermore, our study suggests that it is necessary to establish the age- and sex-specific RIs for serum CYFRA21-1.</p>