Abstract: Objective To compare three assessment methods(TW2,TW2CH,and TW3) for carpal bone age and their potential applications in diagnosis of idiopathic precocious puberty(IPP) in Chinese girls.Methods Fifty-five(55) girls with IPP and 83 normal girls as control group were selected in this study.The X-ray films of the left hand-wrist taken at their first visit were analyzed retrospectively.Three assessment methods were used to estimate the carpal bone age with single-blinded method and percentiles were set at 5 different decision thresholds(1) >97th percentile,(2) >90 th percentile,(3) >75th percentile,(4) >50 th percentile,and(5) ≤50 th percentile.Results All of the three methods showed similar high sensitivity and specificity at the threshold above 90th percentile.Conclusion Our data indicate that all of the three methods for estimation of the carpal bone age are useful in diagnosis of IPP.TW2CH and TW3 methods appear to be superior to TW2 method.

Key words: bone age estimation, TW2 methods, TW3 method, idiopathic precocious puberty, diagnostic usefulness