Usefulness and limitation of punched-out orchidometer in testicular volume measurement

To determine the limitations of a punched-out orchidometer in practical use, we compared with a scrotal ultrasound (USG).

A total of 281 testes from 142 males were examined using both a punched-out orchidometer and a USG. The volume differential between both methods was calculated and expressed as orchidometer/USG volume (O/U ratio). Distribution of the O/U ratio was determined and subdivided by clinical or pathological diagnosis. The correlations between the O/U ratio and patient age or orchidometer results were assessed.

There was a significant linear relationship between the results of orchidometer and USG (r=0.94, P <0.0001). The relationship between the O/U ratio and age or testicular volumes showed significant inverse correlations (r=0.22, P=0.0002, r=0.45, P <0.0001, respectively). Klinefelter's syndrome, ipsilateral detorted testes and hypogonadotropic hypogonadism comparatively showed a high O/U ratio. No incidental lesion was detected by USG necessitating treatment.

The punched-out orchidometer gives estimates that correlated well with the USG measurements and provides enough information for routine andrological evaluation. We should be aware that the orchidometer often overestimates the testicular volume, especially for the patients with small testis or adolescents.