Table 3.

Clinical sensitivity and specificity of the Xpert MTB/RIF RUO assay and the IS6110 LDT using culture as the gold standard

Test% value (no. of specimens positive by NAAT/no. of specimens positive by culture)
Xpert MTB/RIF RUO assayIS6110 LDT
All sites (n = 112)
    Sensitivity, all92 (34/37)81 (30/37)
    Sensitivity, smear positive100 (28/28)100 (28/28)
    Sensitivity, smear negative67 (6/9)22 (2/9)
    Specificity95 (71/75)95 (71/75)
Pulmonary sites (n = 89)
    Sensitivity, all93 (27/29)90 (26/29)
    Sensitivity, smear positive100 (24/24)100 (24/24)
    Sensitivity, smear negative60 (3/5)40 (2/5)
    Specificity97 (58/60)97 (58/60)
Extrapulmonary sites (n = 23)
    Sensitivity, all88 (7/8)50 (4/8)
    Sensitivity, smear positive100 (4/4)100 (4/4)
    Sensitivity, smear negative75 (3/4)0 (0/4)
    Specificity87 (13/15)87 (13/15)