RESUMEN
Tuberculosis is an endemic disease in Iran which may occur mor frequently among hemodialysis patients. We have evaluated tuberculin skin test [TST] in hemodialysis patients in a university hospital in 2003 - 2004. Materials and methods: Sixty-seven hemodialyis patients were enrolled for tuberculin skin tests. Indurations were measured 48 - 72 hours after the injection and then on the 7th day. Those with indurations less than 5mm in TST1 were introduced for TST2. Of 67 patients, 18 [26.9%] had indurations of less than 5mm in TST1 and were introduce for TST2 among whom 7 [39%] had an induration measured less than 5mm. Of 18 cases, 11 [61%] were revealed to have booster effect that represent a ratio of 16% of all studied hemodialysis patients in our study. It seems that the second TST is a better indicator of infectivity in hemodialysis patients, especially for patients who require repeated or annual estimation for M. tuberculosis infection. Keywords: hemodialysis, Booster effect, Tuberculosis, Tuberculin skin test