Table 2 Comparative performance of AFB Smear, Culture and two in house PCR dot-blot methods in PTB suspects
Laboratory Results and Performance of methods | All Groupsa N = 277 | TB non-treated Groupb N = 203 | TB in the past Groupc N = 74 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
TB N = 128 | Non-TB N = 149 | TB N = 109 | Non-TB N = 94 | TB N = 19 | Non-TB N = 55 | ||||||||
Performance of AFB smear | Positive | 77 | 1 | 68 | 0 | 9 | 1 | ||||||
Negative | 51 | 148 | 41 | 94 | 10 | 54 | |||||||
SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | ||
60 | 99 | 99 | 74 | 62 | 100 | 100 | 70 | 47 | 98 | 90 | 84 | ||
CI 95(%) | 51.5-68,4 | 96,7-99,9 | 93.8-99.9 | 67,9-80,0 | 53,0-71,1 | 96,8-100 | 95,7-100 | 61,5-76,9 | 26,1-69,4 | 91,3-99,9 | 59,6-99,5 | 73,9-91,8 | |
Performance of Culture | Positive | 107 | 0 | 94 | 0 | 13 | 0 | ||||||
Negative | 21 | 149 | 15 | 94 | 6 | 55 | |||||||
SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | ||
84 | 100 | 100 | 88 | 86 | 100 | 100 | 90 | 68 | 100 | 100 | 90 | ||
CI 95(%) | 76,4-89,3 | 98,0-100 | 97,2-100 | 82,0-91,9 | 78,8-91,8 | 96,8-100 | 96,8-100 | 78,8-91,8 | 45,5-86,1 | 94,7-100 | 79,4-100 | 80,7-95,9 | |
Performance of PCR dot-blot | Positive | 95 | 22 | 83 | 13 | 12 | 9 | ||||||
Negative | 33 | 127 | 26 | 81 | 7 | 46 | |||||||
SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | ||
74 | 85 | 81 | 81 | 76 | 87 | 86 | 76 | 63 | 84 | 57 | 86 | ||
CI 95(%) | 66,1-81,2 | 78,8-90,3 | 73,3-87,5 | 72,6-85,1 | 67,5-83,4 | 78,0-92,1 | 78,5-92,2 | 66,9-83,1 | 40,3-82,2 | 72,1-91,7 | 35,7-76,7 | 75,6-94,0 | |
Performance of PCR-AG | Positive | 55 | 35 | 46 | 27 | 9 | 8 | ||||||
Negative | 73 | 114 | 63 | 67 | 10 | 47 | |||||||
SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | SE (%) | SP (%) | PPV (%) | NPV (%) | ||
43 | 76 | 61 | 61 | 42 | 71 | 63 | 51 | 47 | 85 | 53 | 82 | ||
CI 95(%) | 34,6-51,7 | 69,2-82,8 | 50,8-70,5 | 53,8-67,8 | 33,2-51,4 | 61,5-79,7 | 51,5-73,5 | 42,9-60,0 | 26,1-69,3 | 74,2-93 | 29,7-75,2 | 70,9-90,7 | |