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Table 4 True- and false-positive results a when changing from QFT-IT to T-Spot in screening for LTBI

From: Implications of the impact of prevalence on test thresholds and outcomes: lessons from tuberculosis

Country

LTBI prevalenceb

Increase in true positivesa,c

Increase in false positivesa,c

Increase in false positives for every true positive gained

United States

4.70%

329

12,389

37.7

Mexico

28.82%

2,018

9,253

4.6

Brazil

38.74%

2,712

7,964

2.9

Thailand

46.74%

3,272

6,924

2.1

Ivory Coast

54.62%

3,823

5,900

1.5

  1. LTBI, latent tuberculosis infection; QFT-IT, QuantiFERON-TB Gold In-Tube; T-Spot, T-SPOT.TB.
  2. a Based on a hypothetical population of 100,000 tested individuals.
  3. bSource: World Health Organization Global TB Database[4].
  4. c Sensitivity estimates: QFT-IT 81%, T-Spot 88%; specificity estimates: QFT-IT 99%, T-Spot 86%.
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BMC Research Notes

ISSN: 1756-0500

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