Inter-observer variation in the results of the clinical andrological examination including estimation of testicular size

Inter-observer variation in andrological examination by 10 clinical investi gators from five Nordic and Baltic countries was investigated. In addition, information on intra-observer variation was obtained for six of the 10 inv estigators. Testicular size was measured using Prader's orchidometer and on e of the investigators also performed an ultrasound estimate of testicular size. A highly significant difference (p < 0.001) between observers was fou nd with an inter-observer error of 16% in estimating testicular size in 23 young men. The difference in the estimate tended to increase with increasin g testicular size. There was no significant intra-observer difference in tw o measurements performed on consecutive days. Only differences in median te stis size, which were greater than 31% between measurements by two investig ators, were found to be significant at the 5% level. The ultrasound estimat e of testicular size was significantly lower than the orchidometer estimate , with a mean difference of 3.6 mL for the left testis and 4.3 mL for the r ight testis. Tanner staging of genitalia and diagnosis of a varicocele was subject to great inter-observer variation, and for the diagnosis of varicoc ele only one-third of the investigators was able to reproduce their results on a second examination. In conclusion, it was found that the clinical andrological examination of y oung men is subject to great inter-observer variation. This should be kept in mind when results from different studies are compared as well as in dail y clinical practice.