Table 1.
QFT categories and IFN-γ results stratified by sputum smear and culture results after 2 months of treatmenta
| Test result after 2 mo of treatment | At diagnosis |
After 2 mo of treatment |
||||
|---|---|---|---|---|---|---|
| No. of QFT-positive patients/total no. of patients (%) | Odds ratio (95% CI) for QFT positiveb | Median IFN-γ value (IU/ml) (IQR)c | No. of QFT-positive patients/total no. of patients (%) | Odds ratio (95% CI) for QFT positive | Median IFN-γ value (IU/ml) (IQR) | |
| Smear | ||||||
| Negative | 31/33 (94) | 1.6 (0.1, 40) | 9.5 (2.2, 9.8) | 30/33 (91) | 2.5 (0.2, 30) | 4.9 (1.2, 9.2)d |
| Positive | 5/5 (100) | 4.3 (1.1, 4.7) | 4/5 (80) | 2.6 (0.7, 3.7) | ||
| Culture | ||||||
| Negative | 46/52 (89) | 0.6 (0.03, 13) | 8.2 (1.8, 9.7) | 43/52 (83) | 0.96 (0.1, 9.2) | 3.6 (0.9, 8.5)e |
| Positive | 6/6 (100) | 9.0 (1.0, 9.9) | 5/6 (83) | 9.8 (1.2, 9.9) | ||
Patients were either smear positive or culture positive (and smear negative) at the time of diagnosis. Qualitative QFT and quantitative IFN-γ results are reported stratified by smear or culture result after 2 months of treatment. Abbreviations: QFT, QuantiFERON-TB gold in-tube assay; IFN-γ, gamma interferon; 95% CI, 95% confidence interval; IQR, interquartile range.
Odds ratio of a positive QFT result with respect to a smear/culture status after 2 months of treatment. In order to calculate the odds ratio, 0 in 2-by-2 table was replaced with 0.5.
The median IFN-γ value is shown in international units per milliliter. The interquartile ranges are shown in parentheses.
The median IFN-γ values for smear-negative and smear-positive patients after 2 months of treatment were nonsignificantly different (P = 0.68) by the Kruskal-Wallis test.
The median IFN-γ values for culture-negative and culture-positive patients after 2 months of treatment were nonsignificantly different (P = 0.16) by the Kruskal-Wallis test.