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. 2016 May 23;54(6):1520–1527. doi: 10.1128/JCM.00017-16

TABLE 2.

Results of direct fluorescent AFBa smear microscopy, SMF, and Xpert MTB/RIF by HIV status in 1,016 pulmonary tuberculosis suspects in Mbarara, Uganda

Method by HIV status Number of test results with valid results by reference standard
 Number positive for test: % sensitivity (95% CIb) Pc Number negative for test: % specificity (95% CIb) Pc
M. tuberculosis detected M. tuberculosis not detected Contaminated
HIV-infected stratum
    Reference standard (MGIT)d 146 527 40
    Comparison of direct AFB to SMFe
        Direct AFB EM + spotf for SMF comparison 135 + 134 479 + 488 30 + 35 183: 68.0 (60.6 to 74.6) 0.81 959: 99.2 (97.9 to 99.7) 0.79
        SMF EM + spotf 136 + 134 479 + 481 29 + 35 18: 67.4 (59.9 to 74.1) 956: 99.3 (98.2 to 99.7)
    Comparison of direct AFB or SMF to Xpert MTB/RIFe
        Xpert MTB/RIF 134 479g 34 122: 91.0 (85.0 to 94.8) 464: 96.9 (94.9 to 98.1)
        Direct AFB spot for Xpert comparison 135 491 35 93: 68.9 (60.6 to 76.1) <0.001 488: 99.4 (98.2 to 99.8) 0.003
        SMF for Xpert comparison 134 482 29 + 35 90: 67.2 (58.8 to 74.5) <0.001 478: 99.2 (97.9 to 99.7) 0.011
HIV-uninfected stratum
    Reference standard (MGIT)d 85 212 6
    Comparison of direct AFB to SMFe
        Direct AFB EM + spotf for SMF comparison 76 + 76 197 + 200 6 + 6 122: 80.3 (70.8 to 87.2) 0.067 390: 98.2 (95.6 to 99.3) 0.56
        SMF EM + spotf 74 + 75 196 + 200 6 + 6 108: 72.5 (62.1 to 80.9) 388: 98.0 (95.4 to 99.1)
    Comparison of direct AFB or SMF to Xpert MTB/RIFe
        Xpert MTB/RIF 77 197 † 6 72: 93.5 (85.7 to 97.2) 190: 96.4 (92.8 to 98.3)
        Direct AFB spot for Xpert comparison 79 199 6 64: 81.0 (71.0 to 88.1) 0.001 196: 98.5 (95.7 to 99.5) 0.044
        SMF for Xpert comparison 75 200 6 54: 72.0 (61.0 to 80.9) <0.001 196: 98.0 (95.0 to 99.2) 0.24
a

AFB, acid-fast bacilli.

b

CI, confidence interval.

c

Since all comparisons used multiple results per person, P values were calculated using the generalized estimating equations score test.

d

Reference standard was based on manual MGIT liquid culture (three samples), with the final MGIT culture result determined as a composite of three values; any positive culture determined a positive composite result.

e

Comparisons of direct AFB versus SMF use an early morning (EM) sample plus a spot sample randomized for SMF testing. Comparisons of direct AFB versus Xpert MTB/RIF use one sample randomized for Xpert MTB/RIF testing. Comparisons of SMF versus Xpert MTB/RIF use one sample randomized to Xpert MTB/RIF.

f

EM, early morning. When two samples from a participant are used for analysis, the number of EM and spot samples was delineated (EM + spot).

g

One Xpert MTB/RIF result was contaminated and excluded.