Two-Step Tuberculin Skin Testing in Drug Users

Abstract

To assess the utility of booster testing and to identify factors associated with a positive booster test, two-step tuberculin testing was performed in drug users recruited from methadone treatment. Participants also received a standardized interview on demographics and testing for HIV and CD4+ lymphocyte count. Of 619 enrollees completing the protocol, 174 (28%) had a positive PPD and 24 of the remaining 445 (5%) had a positive booster test. On multivariate analysis, boosting was associated with older age (adjusted odds ratio [ORadj] 2.38/decade, 95% confidence interval [CI] 1.34-4.22), history of using crack cocaine (ORadj 2.61, 95% CI 1.10-6.18) and a history of working as a home health aide (ORadj 4.23, 95% CI 1.39-12.86). Two-step tuberculin skin testing increased the proportion of participants with latent tuberculosis infection from 22% to 25%. Given the effectiveness of chemoprophylaxis, booster testing should be considered when drug users are screened for tuberculosis infection.

Tuberculosis, injecting drug use and integrated HIV-TB care: A review of the literature

“…Among PWID street-recruited in four US cities, return for TST reading was high for both initial and repeat tests (Table 8), increasing LTBI detection by 41% (Lifson et al, 1997). In New York, PWUD recruited from a methadone programme showed similar initial return rates but lower uptake of booster testing, increasing LTBI detection by just 14% (Swaminathan et al, 2007). Though this approach increased screening coverage, not returning for booster-TST reading was independently associated with a history of IDU, homelessness and living in a shelter, and with HIVpositive status (Swaminathan et al, 2007).…”

“…The majority of studies describing models of TB care for PWID were conducted in North America (n = 23) with a small number of examples from Europe (n = 5) and Asia (n = 1) ( Table 7; Batki et al, 2002;Chaisson et al, 2001;Dhingra et al, 2008;Duarte et al, 2011;FitzGerald et al, 1999;Golub et al, 2008;Gourevitch et al, 1999Gourevitch et al, , 1996Graham et al, 1996;Jansa et al, 1998;Juan et al, 2006;Lifson et al, 1997;Lorvick et al, 1999;Malotte et al, 2001Malotte et al, , 1999Malotte et al, , 1998Marco et al, 1998;O'Connor et al, 1999;Paone et al, 1998;Perlman et al, 2003Perlman et al, , 1997Riley et al, 2002;Rusen et al, 1999;Ruutel et al, 2011;Salomon et al, 1999;Scholten et al, 2003;Smirnoff et al, 1998;Snyder et al, 1999;Swaminathan et al, 2007). These interventions can broadly be grouped into six categories ( Fig.…”

“…A further two US studies described incentivised, 'two-step' TST, in which a booster test was offered 1-3 weeks after an initial negative result in order to maximise LTBI detection (Lifson et al, 1997;Swaminathan et al, 2007). Among PWID street-recruited in four US cities, return for TST reading was high for both initial and repeat tests (Table 8), increasing LTBI detection by 41% (Lifson et al, 1997).…”