Correlation of ultrasonographic and orchidometer measurements of testis volume in adults

OBJECTIVE: To determine the correlation between testicular volume measured with an orchidometer or high-resolution scrotal ultrasonography (US) with colour-flow Doppler analysis. PATIENTS AND METHODS: In all, 159 men (mean age 36.6 years) presenting for infertility evaluation underwent both a physical examination by a one experienced examiner and high-resolution US with colour-flow Doppler analysis. An orchidometer was also used to measure testicular volume after stretching the scrotal skin tightly over the testis and after warming with a heating pad. The US was interpreted by a radiologist who had no knowledge of the orchidometer estimates. The volume was calculated as 0.71 x length x width x height. RESULTS: For the right testes the mean orchidometer and US estimates were 18.4 and 18.3 mL, yielding a correlation coefficient of 0.72 (r (2) = 0.52, P < 0.01). On the left the respective values were 17.1 and 16.9 mL, with a correlation coefficient of 0.69 (r (2) = 0.48, P < 0.01). CONCLUSION: Orchidometer estimates of testicular volume correlate closely and very significantly with US estimates in adults. In the hands of an experienced examiner orchidometer measurements provide an accurate, rapid and inexpensive assessment of testicular volume.