Abstract: Objective To survey the reference intervals of serum 25-hydroxy vitamin D(25OH-D) from adults in Hainan area, and provide scientific reference for reasonable supplement of vitamin D. Methods Basic data of 1 978 healthy subjects(1 008 males and 970 females) with similar livelihood background and different ages were collected, and the level of serum 25OH-D was analyzed by electro-chemiluminescence. The subjects were classified according to sex and age, and the results were analyzed statistically. Results The accuracy and precision of the 25OH-D detection system were good, and the levels of serum 25OH-D had non-Gaussian distribution. The reference intervals were established by percentile (P_2.5-P_97.5). There were statistical significances of 25 OH-D between males and females (P<0.01). There was statistical significance between ≤50 years old and ＞50 years old among males and females(P<0.01). The reference interval of males ≤50 years old was 6.77-26.80 ng/mL, and that of males >50 years old was 4.51-19.73 ng/mL. The reference interval of females ≤50 years old was 5.96-24.79 ng/mL and that of females >50 years old was 3.71-16.34 ng/mL. Conclusions The reference interval for specific sex and age should be established for the population of Hainan area.

Key words: 25-hydroxy vitamin D, Adult, Reference interval