Reference Intervals for Alpha-Fetoprotein (AFP) and Carcinoembryonic Antigen (CEA) in Guangxi Zhuang Ethnic Males from the FAMHES Project

Background: Several studies have reported the reference intervals of serum AFP and CEA levels in ethnically diverse populations, but there is a lack of such reference data among Zhuang ethnic males. The aim of this study was to establish the locally validated reference intervals for AFP and CEA in the male population of the Guangxi Zhuang ethnic group. Methods: A total of 283 Zhuang ethnic males, aged 22 to 69 years, were included from the Fangchenggang Area Male Health and Examination Survey (FAMHES) project database. The one-sided upper 95th-percentile limit was used to estimate the reference intervals for serum AFP and CEA. Results: The total non-parametric reference intervals for Zhuang ethnic males were < 4.95 IU/mL (1 IU/mL is equal to 1.21 ng/mL) and < 5.12 ng/mL for AFP and CEA, respectively. Correlation analysis in this study showed AFP and CEA levels were significantly associated with increasing age, whereas no BMI related differences were found after adjustment for age. Conclusions: The present reference intervals for serum AFP and CEA values deviated from that reported in previous studies. Age-specific reference intervals should be performed in clinical laboratories to obtain more precise estimations for the clinical conditions of young adults and elderly people.