Evaluation Of tuberculin skin test and booster effect in hemodialysis patients

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. 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.