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Table 2 Performance Characteristics of Xpert on sediments and raw sputum samples

From: Improved performance of Xpert MTB/RIF assay on sputum sediment samples obtained from presumptive pulmonary tuberculosis cases at Kibong’oto infectious diseases hospital in Tanzania

Performance characteristics of Xpert in Presumptive PTB using LJ culture as a reference method (N = 262)
 Sensitivity (%) Specificity (%) PPV (%) NPV (%) P-value
Performance characteristics of Xpert on sputum sediments using experimental dilution (1:2)
 92 (84–97) 85 (79–90) 74 (67–80) 96 (91–98) 0.0001
Performance characteristics of Xpert on raw sputa using standard dilution (1:2)
 86 (77–93) 86 (77–93) 75 (65–83) 93 (88–96) 0.001
Incremental values
 6 1 1 3  
Performance characteristics of Xpert in HIV Infected presumptive PTB (n = 39)
Performance characteristics of Xpert on sputum sediments using experimental dilution (1:2)
 100 (81–100) 82 (60–95) 81 (64–91) 100 0.0001
Performance characteristics of Xpert on raw sputa using standard dilution (1:2)
 88 (64–99) 86 (65–97) 83 (59–96) 91 (70–99) 0.0001
Incremental values
 12 4 2 9  
  1. NB: The Xpert MTB/RIF assay have been abbreviated as Xpert