Background: Measurement of testicular volume is important when conditions associated with a delay or advance in the onset of puberty, or micro- and macroorchidism, are suspected. Measured testicular volumes must be compared with reference data, preferably expressed in S.D. curves using the LMS method, as is routinely done for many auxological measurements in pediatrics. The current study therefore aimed to construct LMS-smoothed age-reference charts for testicular volume in healthy children and adolescents.
Methods: Data from a recently published large cross-sectional study on testicular growth in 769 healthy Dutch boys aged 0.519.0 years were used. Testicular volume was measured both with ultrasonography (π/6×length×width×height) and the Prader orchidometer (ellipsoid models ranging in volume from 1 to 25 ml). For each testis, the highest of three measurements was used, and the volumes of both testes were averaged. The reference distributions were fitted by the LMS method, which summarizes the distribution by three age-dependent smooth curves representing skewness (L curve), median (M curve) and coefficient of variation (S curve), and assumes that the data follow a standard normal distribution after a Box-Cox transformation.
Results: Standardized reference charts, allowing the calculation of SDs, and reference curves, allowing easy follow-up of testicular volume in clinical practice, were constructed. The ratio between testicular size assessed with the Prader orchidometer and ultrasonography changed from 3.9 to 2.0 between 0.519.0 years. Based on these charts, no revision of the definition of male precocious or delayed puberty is warranted.
Conclusions: This study allows clinicians and researchers to calculate age-corrected SDs for testicular volume measured either with ultrasonography or orchidometer. The results will aid in the diagnosis and follow-up of abnormalities in the timing and progression of male puberty, as well as micro- or macroorchidism.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology