Accuracy of Prader orchidometer in measuring testicular volume

Abstract

BACKGROUND: Seminiferous tubules comprise 80-90% of testicular mass. Thus, the testicular volume is believed to be an index of spermatogenesis. Therefore, accurate testicular volume is one way to assess testicular function. OBJECTIVE: To determine the accuracy of Prader orchidometer for measuring the testicular volume by comparing the resultant measurement with the actual testicular volume in humans. MATERIALS AND METHODS: The testicular volumes of 121 testes from 62 patients with prostate cancer (mean age 72.74 ± 9.38 years) were measured using Prader orchidometer before therapeutic bilateral orchidectomy. The actual testicular volumes were then determined by water displacement of the testis. RESULTS: The mean testicular volume of the 121 testes was 10.60 ± 3.5 ml and 13.26 ± 5.2 ml for water displacement and Prader orchidometer measurements, respectively. A strong correlation was found between the actual testicular volume and volumes obtained by Prader orchidometer ( r = 0.926, P = 0.0001). The Prader orchidometer however, over-estimated the mean actual testicular volume by 2.66 ± 2.37 ml (25.10%). CONCLUSION: The result of this study has shown that measuring the testicular volume by Prader orchidometer overestimates the actual testicular volume.