BMC Public Health 2007, 7:356 http://www.biomedcentral.com/1471-2458/7/356 Table 2: Performance of Culture, PCR dot-blot and Clinical suspicion tests, individually and associated, in 151 smear negative PTB suspects Table 2A. Laboratory results and Performance of methods All Groupa N = 151 Non previously TB treated Groupb N = 98 Culture PCR dot-blot High PP Intermediate PP Low PP Positive Negative Positive Negative Positive Negative Positive Negative Positive Negative Table 2B. Performance of methods used in parallel Performance of PCR dot-blot in parallel with High Clinical Suspicion Performance of PCR dot-blot in parallel with Intermediate Clinical Suspicion 70% 68% 68 70 74% 77% 75 Performance of PCR dot-blot in parallel with Low Clinical Suspicion SE SP PPV NPV SE SP PPV 26% 25% 47 47 26% 14% 45 SE: Sensitivity, SP: Specificity, PPV: Positive Predictive Value, NPV: Negative Predictive Value, PP: pretest probability (clinical suspicion). a: All group. b: Non previously TB treated group patients TB N = 43 30 13 SP 100% 28 15 31 12 6 37 6 37 SP 83% SP 86% SP 82% SP 31% SP 71% SP SE 70% SE 65% SE 72% SE 14% SE 14% SE 90% SE Non-TB N = 108 0 108 PPV 100 PPV 61 PPV 67 PPV 24 PPV 7.5 PPV 75 PPV 18 90 15 93 19 89 74 34 NPV 89 NPV 86 NPV 88 NPV 71 NPV 48 NPV 88 NPV SE 75% SE 69% SE 72% SE 17% SE 11% SE 91% SE TB N = 36 27 9 25 11 26 10 6 30 4 32 SP 100% SP 85% SP 93% SP 90% SP 16% SP 79% SP PPV 100 PPV 73 PPV 87 PPV 50 PPV 7.1 PPV 81 PPV Non-TB N = 62 0 62 9 53 4 58 6 56 52 10 NPV 87 NPV 83 NPV 85 NPV 65 NPV 24 NPV 90 NPV 76 NPV 34 Page 5 of 10 (page number not for citation purposes)