Evaluation Of tuberculin skin test and booster effect in hemodialysis patients

Background: Tuberculosis is an endemic disease in Iran which may occur more 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. Results: 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. Conclusion: 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.