Evaluation of testicular volume by three orchidometers compared with ultrasonographic measurements

Objective To investigate the accuracy of three commonly used orchidometers (Prader, Takihara punched-ring and Seager) compared with ultrasonography (US) for the measurement of testicular size. Subjects and methods A prospective, randomized, blinded trial to compare three methods of measuring testicular volume was performed, involving 31 men attending the Fertility Problems Clinic for the assessment of fertility. Testicular size was measured independently by three doctors and compared with estimates obtained independently by US in the Radiology department. Results The Prader and Takihara punched-ring orchidometers consistently overestimated testicular size compared with that estimated by US. A substantial proportion of the measurements obtained using the Prader orchidometer were more than twice the value estimated by US. Conclusions The Prader and Takihara orchidometers were useful in comparing different testicular sizes but the absolute values obtained would probably be overestimated in many clinical situations. The Seager orchidometer, although more difficult to use, agreed best with the US estimates.