To establish and verify the reference intervals of serum osteocalcin (OST) data were used in different age groups based on the serum OST data of physical examination population.

Serum OST data from health checkup specimens sent to Guangzhou KingMed Center for Clinical Laboratory from January 2017 to June 2023 were collected. Skewness-Kurtosis was used to analyze the normality of data, and Tukey method and box graph method were used to eliminate outliers. Data were grouped by Mann-Whitney U, Kruskal-Wallis H and Z tests. Reference intervals and 95% confidence intervals were established according to the non-parametric method in Guideline EP28-A3, and qualified physical specimens were screened for verification of the reference intervals.

The data collected in this study encompassed individuals from 17 provinces or municipalities in China, including 10 294 males and 9664 females. The reference ranges of serum OST in different age groups were as follows: For males, ≤ 18 years old is 18.13-97.35 ng/ml, 19-29 years old is 9.94-26.76 ng/ml, 30-39 years old is 8.70-24.05 ng/ml, 40-49 years old is 7.81-22.71 ng/ml, 50-59 years old is 6.69-22.69 ng/ml, ≥ 60 years old is 6.26-22.50 ng/ml; for females,≤18 years old is 10.17-107.23 ng/ml, 19-29 years old is 7.63-24.45 ng/ml, 30-39 years old is 6.91-22.37 ng/ml, 40-49 years old is 6.47-22.83 ng/ml, ≥ 50 years old is 7.73-30.38 ng/ml. The reference ranges for each age group have been validated. Serum OST levels differed significantly across male age groups (all P<0.001), showing a progressive decline with age. Among females, serum OST levels decreased sequentially from the ≤18 years group to the 30-39 years group (all P<0.001), with no significant difference between the 30-39 years and 40-49 years groups (P>0.05). The 50-59 years group exhibited higher levels than the 40-49 years group (P<0.001), while no significant difference was observed between the 50-59 years and ≥60 years groups (P>0.05), indicating an overall pattern of initial decline followed by an increase. Gender comparisons revealed that males aged 19-29, 30-39, and 40-49 years had significantly higher serum OST levels than females in the same age groups (all P<0.001), whereas males aged 50-59 and ≥60 years had lower levels than their female counterparts (all P<0.001).

This study established reference ranges of serum OST in different age groups of Chinese, providing a valuable reference for the application of serum OST across various age brackets.