Friedrich 2011

Study characteristics
Patient sampling	Cross‐sectional design, consecutive enrolment, prospective data collection
Patient characteristics and setting	Presenting signs and symptoms: people recently diagnosed with smear‐positive first time TB, untreated Age: 18 to 65 years Sex, female: not reported HIV infection: not reported History of TB: not reported Sample size: 126 Clinical setting: smear examination at TB clinic and referred to inpatient settings Laboratory level: central Country: South Africa, Cape Town World Bank Income Classification: middle income High TB burden country: yes High MDR‐TB burden country: yes High TB/HIV burden country: yes TB incidence rate: 993 per 100,000 MDR‐TB prevalence: % MDR‐TB among new TB cases = 0.9% (Source: survey in Western Cape Province, 2002) and among retreatment cases = 4.0% (Source: survey in Western Cape Province, 2002) Prevalence of TB cases in the study: 100.0%
Index tests	Index: Xpert MTB/RIF
Target condition and reference standard(s)	Target condition: pulmonary TB Reference standard for pulmonary TB: MGIT 960 Target condition: rifampicin resistance Reference standard for rifampicin resistance: MGIT 960
Flow and timing
Comparative
Notes	The aim of this study was to assess NAATs for selecting participants for clinical trials of anti‐TB medication. People with severe co‐morbidities were excluded. This study was used only for determination of sensitivity because all enrolled participants were predetermined to have TB disease
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	No
		High	Low
DOMAIN 2: Index Test Xpert MTB/RIF
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Yes
		Low	Unclear
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results for TB detection interpreted without knowledge of the results of the index test?	Yes
Were the reference standard results for rifampicin resistance detection interpreted without knowledge of the results of the index test?	Yes
		Low	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
		Low