Testicular Volume Measurement: Comparison of Prader′s Orchidometry, Ultrasonography, and Actual Volume by Water Displacement

Objectives: To assess the accuracy of Prader′s orchidometer and ultrasonography in estimating the volume of testis against the actual volume of testis as measured by Archimedes principle of water displacement. Subjects and Methods: Fifty-six patients with advanced prostate cancer had an estimation of testicular volume by Prader′s orchidometer by the same urologist and ultrasonography by the same radiologist. Lambert′s formula was used for calculating the volume of testis. All patients underwent bilateral orchiectomy, and the actual volume of the testes was estimated by the water displacement method. Results: Mean age of patients was 71.53 years. The reliability of both the methods was calculated by Bland-Altman plot. The discrepancy of individual measurement and the bias (average discrepancy) was calculated for each method separately, and the plot was derived. In both the plots, the values were more concentrated around the value 0, showing that both were reliable in measuring the volume accurately. Conclusions: The volume of testis measured by Prader′s orchidometer correlated with that measured by ultrasonography as well as the actual volume measured by water displacement method. This method is hence useful in office practice, community screening, adolescent clinics, and teen clinics.