This article is more than 5 years old. Information may no longer be current.
Blood assays outperform skin test in TB diagnosis
Click Here to Manage Email Alerts
The Quantiferon-TB Gold In-Tube Assay and the T-Spot.TB assay outperformed the tuberculin skin test in sensitivity and specificity, according to recently published meta-analysis results.
Roland Diel, MD, of Medical School Hannover in Hannover, Germany, and colleagues used Medline, EMBASE and Cochrane bibliographies to perform the meta-analysis of 124 studies.
The researchers examined 25 studies that specifically reviewed the sensitivity of the TST test, 19 studies that reviewed the sensitivity of the Quantiferon-TB Gold test and 17 studies that reviewed the sensitivity of the T-Spot.TB assay. Pooled sensitivity was 70% (95% CI, 0.67-0.72) for the tuberculin skin test, 81% (95% CI, 0.78-0.83) for the Quantiferon-TB Gold In-Tube Assay and 88% (95% CI, 0.85-0.90) for the T-Spot.TB.
When the analysis was restricted to performance in developed countries, the sensitivity increased to 84% (95% CI, 0.81-0.87) for the Quantiferon assay and 89% (95% CI, 0.86-0.91) for the T-Spot.TB assay.
Specificity was 99% (95% CI, 0.98-1.00) for the Quantiferon assay and 86% (95% CI, 0.81-0.90) for the T-Spot.TB assay. By comparison, TST specificity may be as low as 59% in people who are BCG-vaccinated and only 97% in non-vaccinated populations.
Diel R. CHEST. 2010;137:4 952-968.