Tuberculin skin test and isoniazid prophylaxis among health care workers in high tuberculosis prevalence areas

The tuberculin skin test (TST) is an important tool for the detection of latent tuberculosis (TB) and the identification of health care workers (HCWs) who require chemoprophylaxis. Although TST is inexpensive, easily available and the preferred test in most TB-prevalent settings, it has recognised limitations, including subjective interpretation, false positivity, cross reactivity with nontuberculous mycobacteria, administration errors and the requirement for two visits. Given these limitations and the unavailability of better screening tests in resource-limited settings, the acceptance rate for chemoprophylaxis among HCWs has remained low. Furthermore, chemoprophylaxis in these settings is complicated by the high rate of drug-resistant TB, potential adverse reactions, prescription of chemoprophylaxis in undiagnosed active TB patients and the unavailability of follow-up systems provided by occupational health programmes. In the present article, we provide our viewpoint and a practical approach along with existing evidence supporting or discouraging the use of TST and isoniazid chemoprophylaxis for TB screening and management among HCWs in TB-prevalent settings.