Concordance of testicular measurement in male adolescents with three methods of orchidometry

Abstract

Introduction. The Prader orchidometer is the standard method used to measure testicular volume (TV) in children and adolescents. Objective. To assess the concordance in the estimation of TV and puberty onset with the Prader, Chipkevitch, and Sotos orchidometric techniques. Methods. Cross-sectional descriptive study conducted among male children and adolescents aged 9-20 years. For each adolescent, TV was measured with the methods by Prader (gold standard), Chipkevitch (graphic model), and Sotos (measurement of testicular width with a plastic ruler and use of a formula equivalent to the ellipsoid equation). Male children and adolescents with urogenital conditions and disorders affecting testicular growth were excluded. Kappa statistics was used to determine concordance among methods for puberty onset, and intraclass correlation coefficient (ICC) and Bland-Altman (B&A) plots for TV. Results. In total, 377 healthy males were included. Regarding the concordance for TV (mL), the Prader-Chipkevitch comparison obtained an ICC of 0.994 and a p < 0.001; while the Prader-Soto comparison obtained an ICC of 0.312 and a p < 0.001. With the B&A plots, mean differences were close to 0 mL in the Prader-Chipkevitch comparison and close to 8 mL in the Prader-Sotos comparison. Concordance for puberty onset obtained a kappa value of 0.93 and 0.75 in the Prader-Chipkevitch and Prader-Sotos comparisons, respectively. Conclusion. The Prader and Chipkevitch orchidometers show an excellent concordance in estimating TV and puberty onset; therefore, both methods could be used interchangeably in the daily care of male adolescents. The Sotos method showed a high concordance in estimating pubertal onset, but low in measuring TV.