Risk-based screening for latent tuberculosis infection.

BACKGROUND

National guidelines recommend targeted tuberculin testing and treatment of latent tuberculosis infection (LTBI) among high-risk groups but discourage testing low-risk persons.

METHODS

We determined the LTBI prevalence (tuberculin skin test [TST] reaction > or = 10 mm) among adults with and without TB exposure risk factors screened in Tennessee from 1/2/2002 to 4/19/2005. We then quantified LTBI risk among groups at high-risk for TB using multivariate analysis.

RESULTS

Of 53,061 adults tested, the LTBI prevalence was 34% among foreign-born persons, compared with 3.2% among nonforeign-born persons (prevalence odds ratio [POR] 15.7, 95% confidence interval [CI] 14.5-16.8). Among nonforeign-born adults, Asian race (POR 11.7, 95% CI 5.9-23.4), and Hispanic ethnicity (POR 11.7, 95% CI 9.0-15.2) were most strongly associated with LTBI. Only 2.4% of low-risk persons had LTBI.

CONCLUSIONS

Risk-based screening can effectively distinguish persons who will benefit from LTBI testing and treatment. Targeted testing programs should prioritize foreign-born persons. Testing of low-risk persons is unnecessary.