Diagnosing impotence.

Although psychogenic factors have been thought to account for 95% of cases of impotence, current research indicates that organic factors may be present in about 50%. Investigation of impotence therefore involves a complete history and physical examination, psychological evaluation, an interview with the patient's partner, tests for serum testosterone level, urological assessment, and measurement of nocturnal penile tumescence. Referral to a sexual dysfunction clinic should take place if the etiology remains obscure. Above all, thoroughness of approach and empathy for the patients is paramount.