Comparison of an ESAT-6/CFP-10 peptide-based enzyme-linked immunospot assay to a tuberculin skin test for screening of a population at moderate risk of contracting tuberculosis.
Screening for latent tuberculosis infection (LTBI) with the Mantoux tuberculin skin test (TST) has many limitations including false-positive results due to Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination. Three hundred ninety adult inmates with normal screening chest radiographs in a county jail were evaluated for LTBI using TST and an ESAT-6/CFP-10 peptide-based enzyme-linked immunospot assay (T-SPOT.TB). LTBI prevalence rates were 19.0% and 8.5% by T-SPOT.TB and TST, respectively. Overall agreement between test results was 82.8% (kappa = 0.29). Positive T-SPOT.TB results were significantly associated with increased age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01 to 1.06) and intravenous drug use history (OR, 2.92; 95% CI, 1.36 to 6.27). Positive TST results were significantly associated with increased age (OR, 1.06; 95% CI, 1.02 to 1.09) and foreign birth (OR, 6.61; 95% CI, 1.98 to 22.01). Discordant covariates between the assay results included increased age (OR, 0.96; 95% CI, 0.94 to 0.99) and intravenous drug use history (OR, 0.41; 95% CI, 0.19 to 0.88). T-SPOT.TB reactivity is unaffected by prior BCG vaccination. T-SPOT.TB may be more sensitive than TST in diagnosing LTBI among a moderate risk population of inmates, particularly those with intravenous drug use history. Longitudinal studies are needed to assess the positive predictive value of T-SPOT.TB in identifying those most likely to convert to active disease in general populations as well as in high-risk subpopulations.
Porsa
Esmaeil
E
Department of Family and Community Medicine, The University of Texas Health Science Center, Houston, Texas, USA. Esmaeiporsa@yahoo.com
Cheng
Lee
L
Graviss
Edward A
EA
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D007124:Immunoenzyme Techniques; D007159:Immunologic Tests; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D011329:Prisoners / Q000706:statistics & numerical data; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013781:Texas / Q000453:epidemiology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D044465:White People / Q000706:statistics & numerical data
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis