Assessment of the prevalence of latent tuberculosis infection in hemodialysis patients using tuberculin skin test

Abstract

Introduction: Patients undergoing dialysis are suffering from some degree of cellular immunity impairment which predispose them to develop latent tuberculosis infection (LTBI) which can turn into active tuberculosis (TB). Diagnosing LTBI in dialysis patients is helpful in preventing disease evolution. Objectives: The aim of this study was to estimate the frequency of LTBI in a group of hemodialysis patients. Patients and Methods: We studied all patients undergoing hemodialysis in Khorramabad teaching hospitals. Data were collected by completing a questionnaire through observation and interview. The Mantoux tuberculin skin test (TST) was performed, then 48 to 72 hours later, the induration was measured in millimeters. Results equal to or greater than 10 mm were considered positive. Results: One hundred and nineteen patients undergoing hemodialysis participated in the study. The mean age of patients in this study was 58.55 ± 16.04 years. The induration size at the TST site was equal to or greater than 10 mm for 97 patients (81.5%) and less than 10 mm for 22 patients (18.5%). More than 81% of participants had LTBI. Until about two years later, none developed active tuberculosis without preventive treatment. Conclusion: Several studies indicate the uncertainty of TST results in hemodialysis patients. Eighty-two percent positive is too much, and makes it difficult to consider all of them to be true positives. Therefore, it will be challenging to decide on starting preventive treatment. We recommend World Health Organization (WHO) to focus on a new affordable accessible efficient test for LTBI screening which does not require to be repeated or be confirmed by another diagnostic method, especially, for the expanded screening of the general population in the future.