Ultrasound measurements of testicular volume: Comparing the three common formulas with the true testicular volume determined by water displacement

ObjectiveTo determine the accuracy of various ultrasound formulas for measuring the testicular volume in humans by comparing the resultant measurements with the actual testicular volume.Subjects and methodsThe testicular volume of 121 testes from 62 patients with prostate cancer (mean age 72.7 ± 9.4) was measured using ultrasonography before therapeutic bilateral orchidectomy. The ultrasound measurements of the testicular volume were calculated using the following three formulas: (a) length (L) × width (W) × height (H) × 0.52; (b) L × W2 × 0.52 and (c) L × W × H × 0.71. The actual testicular volume was determined by water displacement of the testis.ResultsThe mean actual testicular volume was 10.6 ± 3.5 ml. A strong correlation was found between the actual testicular volume and the volume calculated by the three-ultrasound formulas (r = 0.853–0.871, p = 0.0001). The smallest mean difference from the actual testicular volume was observed with the formula L × W × H × 0.71, which underestimated the actual volume by 0.4 ml (3.9%).ConclusionThe results of this study show that ultrasonography and the formula L × W × H × 0.71 are the most accurate method for the calculation of the testicular volume.