Rachow 2011

Study characteristics
Patient sampling	Cross‐sectional design, consecutive enrolment, retrospective data collection
Patient characteristics and setting	Presenting signs and symptoms: presumptive pulmonary TB based on clinical and radiographic findings Age: mean 39 years (SD 13.8) Sex, female: 51.7% HIV infection: 58.9% History of TB: not reported Sample size: 249 Clinical setting: referral hospital Laboratory level: central Country: Tanzania World Bank Income Classification: low income High TB burden country: yes High MDR‐TB burden country: no High TB/HIV burden country: yes TB incidence rate: 169 per 100,000 MDR‐TB prevalence: percentage MDR‐TB among new TB cases = 1.1% (Source: nationwide survey, 2007) and among retreatment cases = 0% (Source: Nationwide survey, 2007) Prevalence of TB cases in the study: 27.7%
Index tests	Index: Xpert MTB/RIF
Target condition and reference standard(s)	Target condition: pulmonary TB Reference standard for pulmonary TB: LJ culture and MGIT 960 Target condition: rifampicin resistance Reference standard for rifampicin resistance: MGIT 960
Flow and timing
Comparative
Notes	Participants were followed for a period of 56 days. Among 77 participants classified as smear‐negative, culture‐negative 'clinical TB', Xpert MTB/RIF was positive in 7 (9.1%) participants No participants were found to have rifampicin resistance
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?	Yes
		Low	Unclear
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	Low
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?	Unclear
		Unclear