The diagnosis of tuberculosis in dialysis patients.

Tuberculosis is an important issue for nephrologists caring for dialysis patients. Because dialysis patients are immunocompromised, they are at higher risk for reactivation of latent tuberculosis, and they frequently have atypical presentation. Furthermore, hemodialysis units may foster rapid spread of active pulmonary tuberculosis. The diagnosis of active pulmonary tuberculosis still depends on detection of organisms by smear and culture. Newer nucleic acid detection techniques are more sensitive and specific. Nephrologists should remember that nonspecific presentation of tuberculosis including fever, weight loss, and adenopathy are more common in dialysis patients than in the general population, and diagnosis may require biopsy of extrapulmonary tissue. Detection of latent tuberculosis in dialysis patients should only be undertaken if treatment is planned. Generally, this should apply only to potential transplant candidates and younger dialysis patients with longer life expectancy. Tuberculin skin test is very insensitive in dialysis patients, and false-positives occur in patients born in countries where Bacillus Calmette-Guérin vaccine has been used. Blood tests using stimulation of gamma interferon have been shown to be more sensitive tests of latent tuberculosis and may be used in conjunction with tuberculin skin tests.