Abstract:

Objective To establish the reference intervals of serum 25-hydroxyvitamin D [25（OH）D] among minors in Shanghai. Methods A total of 400 minors （≤16 years old） were enrolled,including 200 boys and 200 girls. They were classified into 5 groups according to ages,<1 month（20 cases）,1-<6 months（80 cases）,6 months-<3 years （100 cases）,3-<6 years（100 cases）and 6-16 years（100 cases）. The level of 25（OH）D was determined by enzyme-linked immunosorbent assay （ELISA）. Results In the results of 400 cases,1 outlier was eliminated. The 25（OH）D levels demonstrated skewed distribution,so its overall level was shown by median （M）[quartiles（P₂₅-P₇₅）]. The 25（OH）D level of 399 cases was 55.64（42.93-76.05） nmol/L,56.47（44.59-76.48） nmol/L for boys and 55.44（41.07-75.55） nmol/L for girls. There was no statistical significance between boys and girls（P>0.05）. There was no statistical significance for different ages （P>0.05）. The 25（OH）D level in the groups of 1-<6 months and 6 months-<3 years were higher than those in the other 3 groups（P<0.05）. The reference intervals should be established according to ages. The reference intervals were shown by percentiles [the 2.5th percentile（P_2.5）-the 97.5th percentile （P_97.5）] and were 32.66-79.33 nmol/L for <1 month group,32.45-129.91 nmol/L for 1-<6 months group,38.98-129.90 nmol/L for 6 months-<3 years group,32.22-86.44 nmol/L for 3-<6 years group and 30.74-87.74 nmol/L for 6-16 years group. Conclusions The reference intervals of 25（OH）D have been initially established for minors in Shanghai.

Key words: 25-Hydroxyvitamin D, Minors, Reference intervals