Use of tuberculin skin test and isoniazid prophylaxis among healthcare workers in developing countries: an un-resolved controversy.

Tuberculosis is one of the most significant causes of infectious morbidity and mortality worldwide and has been an important threat for healthcare workers (HCW) for decades. Although the tuberculin skin test (TST) is less expensive, available and a preferred diagnostic tool for latent tuberculosis infection in most TB-prevalent settings, limitations inclusive of false positivity, cross reactivity with non-tuberculous mycobacteria, interpretative and administrative errors have been described. The acceptance rate of TSTguided chemoprophylaxis among HCW in resource-limited settings has remained low given these recognizable limitations. Isoniazid (INH) has generally been recommended as chemoprophylaxis after a reactive TST. However, the INH treatment in these settings may be complicated by local drug-resistant TB and unavailable infection-control resources and TB control program. Herein we discuss the advantages and disadvantages of utilizing TST and chemoprophylaxis among HCW and unresolved issues that require future research in TB-prevalent settings. (J Infect Dis Antimicrob Agents 2010;27:1-9.) *Division of Infectious Diseases, Faculty of Medicine, Thammasat University Hospital, Pathumthani 12120, Thailand. **Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand. Received for publication: March 9, 2010. Reprint request: Anucha Apisarnthanarak, M.D., Division of Infectious Diseases, Faculty of Medicine, Thammasat University Hospital, Pathumthani 12120, Thailand. E-mail: anapisarn@yahoo.com