Table 7. Combined results of the ELISA with the two sets of 50 sera (27 culture positive PTB and 73 culture negative patients) using selected antigen/antibody combinations.
| TB | No TB | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Antigen or compound number | Method# | Secondary antibody | Smear and culture positive PTB | Culture negative | p value## | ROC AUC (95% interval) | Optimum Cut-off from ROC | Optimum Sensitivity/ Specificity combination from ROC | Cut-off for 100% sensitivity | SpecificityBased on this cut-off | ||
| Median absorbance | IQR | Median absorbance | IQR | Significance relative to n15 | ||||||||
| Human TDM | n15 | IgG (whole) | 3.11 | 2.92–3.37 | 1.72 | 1.09–2.7 | <0.001 | 0.88 (0.80–0.95) | 2.88 | 78/86 | >1.81 | 51 |
| Bovine TDM | n20 | IgG (whole) | 3.1 | 2.86–3.34 | 1.69 | 1.08–2.31 | <0.001 | 0.89 (0.83–0.96) | 2.45 | 89/81 | >1.93 | 58 |
| 6 | n1 | IgG (Fc) | 3.14 | 2.47–3.58 | 0.99 | 0.54–1.79 | <0.001 | 0.87 (0.80–0.94) | 1.26 | 89/81 | >0.54 | 38 |
| 7 | n3 | IgG (Fc) | 2.9 | 1.59–3.41 | 0.95 | 0.53–2.04 | <0.001 | 0.80 (0.71–0.89) | 1.72 | 89/74 | >1.15 | 59 |
| 12 | n4 | IgG (Fc) | 2.78 | 1.63–3.21 | 0.69 | 0.43–1.43 | <0.001 | 0.88 (0.80–0.95) | 1.38 | 85/64 | >0.62 | 38 |
| 13 | n32 | IgG (Fc) | 2.71 | 1.04–3.14 | 0.7 | 0.47–1.25 | <0.001 | 0.81 (0.71–0.91) | 2.14 | 59/93 | >0.37 | 12 |
| 14 | n28 | IgG (Fc) | 3.25 | 2.07–3.55 | 0.72 | 0.4–1.19 | <0.001 | 0.90 (0.83–0.96) | 1.25 | 89/81 | >0.61 | 44 |
| 14 | n1b | IgG (Fc) | 1.1 | 0.49–2.45 | 0.3 | 0.22–0.42 | <0.001 | 0.86 (0.76–0.96) | 0.47 | 79/81 | >0.14 | 1 |
| 15 | n2 | IgG (Fc) | 2.84 | 1.25–3.37 | 0.62 | 0.41–1.17 | <0.001 | 0.83 (0.73–0.93) | 1.52 | 70/86 | >0.22 | 3 |
| 16 | n47 | IgG (Fc) | 1.51 | 0.86–3.27 | 0.37 | 0.27–0.57 | <0.001 | 0.91 (0.86–0.97) | 0.49 | 96/72 | >0.46 | 62 |
| 17 | n37 | IgG (Fc) | 2.97 | 1.41–3.21 | 0.71 | 0.4–1.44 | <0.001 | 0.84 (0.77–0.92) | 0.77 | 100/56 | >0.22 | 49 |
| 18 | n5 | IgG (Fc) | 2.99 | 1.95–3.4 | 0.82 | 0.46–1.47 | <0.001 | 0.87 (0.79–0.94) | 1.92 | 78/82 | >0.84 | 53 |
| 19 | n6 | IgG (Fc) | 3.24 | 2.24–3.78 | 0.97 | 0.56–1.93 | <0.001 | 0.84 (0.75–0.93) | 1.79 | 85/74 | >0.44 | 14 |
| 20 | n39 | IgG (Fc) | 3.25 | 2.97–3.66 | 0.64 | 0.34–1.24 | <0.001 | 0.94 (0.89–0.98) | 1.32 | 100/75 | >1.39 | 77 |
Footnotes:
# Method: as for Table 5.
## Comparison of medians ELISA results from culture positive PTB and culture negative samples. Abbreviations: PTB: pulmonary tuberculosis; IQR: interquartile range. Ab: antibody, TDM: trehalose dimycolate, TMM: trehalose monomycolate ROC: receiver operator characteristics AUC: area under curve TB: tuberculosis