Table 1– Distribution of QuantiFERON®-TB Gold In-Tube (QFT-IT) and interferon-γ-inducible protein (IP)-10 test results and comparison between tests
Test resultSingle-marker testsCombined test
IP-10 test#QFT-IT
HIV-negative+
 Positive75 (82; 72–89)74 (80; 71–88)86 (93; 88–99)##
  Sensitivity86 (79–93)88 (81–95)96 (91–99)##
 Negative12 (13; 7–22)10 (11; 5–19)4 (4; 0–9)##
 Indeterminate5 (5; 2–12)8 (9; 4–16)2 (2; 0–5)¶¶
HIV-positive§
 Positive41 (63; 50–75)ƒ41 (63; 50–75)ƒ46 (71; 60–82)##
  Sensitivity76 (65–87)82 (74–95)88 (80–97)##
 Negative13 (20; 11–32)9 (14; 7–25)6 (9; 2–16)++
 Indeterminate11 (17; 9–28)ƒ15 (23; 14–35)ƒ13 (20; 10–30)
  • Data are presented as n (%; 95% CI) or % (95% CI). Sensitivity was calculated after excluding indeterminate results. Algorithms for test results can be seen in online supplement 1. In the combined approach, the test was deemed positive if either test was positive, negative if both tests were negative and indeterminate if one test was indeterminate and the other was negative. All p-values were calculated using McNemar’s test. #: cut-off 673 pg·mL−1, as determined in 5; : cut-off 0.35 IU·mL−1 (17.5 pg·mL−1); +: n = 92; §: n = 65; ƒ: p<0.05 compared with HIV-negative patients; ##: p<0.05 compared with either single-marker test; ¶¶: p<0.05 compared with the QFT-IT alone; ++: p<0.05 compared with the IP-10 test alone.