Table 1.
Baseline characteristics of determinate and indeterminate IGRA resultsa
| Patient characteristic | Determinate IFN-γ response | Indeterminate IFN-γ response | Overall total |
|---|---|---|---|
| Baseline characteristics (% [no. of positive subjects/total no. of subjects]) | |||
| Female | 66.6 (342/513) | 72.9 (35/48) | 67.2 (377/561) |
| HIV positive | 56.9 (292/513) | 79.2 (38/48) | 58.8 (330/561) |
| TST positive | 61.1 (301/493) | 59.6 (28/47) | 60.9 (329/540) |
| Smoker | 20.7 (106/511) | 8.3 (4/48) | 19.7 (110/559) |
| TB contact | 15.6 (79/507) | 14.6 (7/48) | 15.5 (86/555) |
| Previous episode of TB | 11.5 (59/512) | 14.6 (7/48) | 11.8 (66/560) |
| Presence of BCG scar | 48.1 (246/511) | 66.7 (32/48) | 49.7 (278/559) |
| On ARTb | 1.4 (4/290) | 2.6 (1/38) | 1.5 (5/328) |
| Employed | 30.6 (156/510) | 33.3 (16/48) | 30.8 (172/558) |
| Shack accommodation | 54.6 (261/478) | 61.4 (27/44) | 55.2 (288/522) |
| Resident <1 yr in Khayelitsha | 4.4 (21/476) | 12.9 (6/43) | 5.2 (27/519) |
| Other factors (median [IQR]) | |||
| Age (yr) | 28 (22.7–34.7) | 29.6 (25–35.5) | 28.1 (22.9–34.7) |
| BMI | 25.1 (22.0–30.0)) | 25.8 (23.4–29.3) | 25.2 (22.0–29.8) |
| Education (highest grade) | 11 (10–11) | 11 (10–12) | 11 (10–12) |
| No. of persons/bedroom | 2 (1.67–3) | 2 (1.9–3) | 2 (1.67–3) |
| CD4 count (cells/mm3) | 353 (260–507) | 241 (101–420) | 346.5 (241–502) |
| No. of days since HIV diagnosis | 325 (15–1354) | 255 (43–981) | 322.5 (17–1337) |
| Mantoux skin test result (mm) | 12 (1–20) | 10 (0–17) | 10 (0.5–20) |
a
Characteristics in bold represent significant differences between determinate and indeterminate IFN-γ responses.
b
ART, antiretroviral therapy.