Diagnosis of tuberculosis in dialysis patients: current strategy

Patients with ESRD undergoing chronic dialysis are much more prone to develop tuberculosis (TB) than the general population. In these patients, the diagnosis of TB disease is often difficult because of prevailing extrapulmonary involvement and nonspecific symptoms. The prevalence of latent TB infection (LTBI) in ESRD patients is elevated, and those who become infected are at high risk of developing active disease. Therefore, screening for LTBI in this population is recommended, aiming to prevent progression to active TB and secondary contamination of others. The tuberculin skin test (TST), the classic diagnostic tool for LTBI, has several major drawbacks, including poor sensitivity (because of a high prevalence of anergy in dialysis patients) and specificity [with false-positive tests in those vaccinated with bacille Calmette-Guérin (BCG)]. In the past 10 years or so, new immunological tests using IFN-gamma release assays (IGRAs) have become available and have shown superior sensitivity and specificity for the diagnosis of TB compared with the TST in several studies, some very recent ones including ESRD patients. Therefore, current strategy in dialysis patients should use these tests instead of TST for LTBI screening and as an aid for the diagnosis of active TB.