Comparative assessment of pediatric testicular volume: Orchidometer versusultrasound

Purpose: Testicular volume measurements obtained with the Prader and Roches ter orchidometers were compared to those obtained using scrotal ultrasound. The ability of each orchidometer versus ultrasound in detecting volume dif ferential between 2 testes and the accuracy of orchidometer measurement by a less experienced examiner to that of a urologist were compared. Materials and Methods: A total of 65 males were examined by the attending u rologist and urology nurse using the Prader and Rochester orchidometers, an d scrotal ultrasound was subsequently performed by an attending radiologist . Statistical analysis of the results was performed to determine the correl ation of orchidometer measurements between examiners, as well as with ultra sound, and sensitivity and specificity of orchidometer and ultrasound in de tecting defined volume differentials between testes of 10%, 15%, 20% and 25 %. Results: There was a strong linear relationship between testicular volume m easurements using either orchidometer and ultrasound. To detect a defined v olume differential as determined by ultrasound orchidometer sensitivity was weak, whereas orchidometer specificity was better. There was a strong corr elation between orchidometer measurements of the urology nurse and attendin g urologist. Conclusions: Although the orchidometer remains valuable in assessing size o f the individual testis, it is too insensitive to volume differentials rela tive to ultrasound to be used routinely to determine growth impairment. For this reason observation of an adolescent with varicocele should include an annual ultrasound assessment of testicular volume.