Table 1.
The 12 combinations of screening methods and confirmatory tests
| Number | Screening method | Confirmatory test | ||
|---|---|---|---|---|
| First | Second (if 1st positive) | First | Second (if 1st negative) | |
| 1 | Prolonged cough* | SSM | CD§ | |
| 2 | Prolonged cough* | XP | CD§ | |
| 3 | Prolonged cough* | CXR‡ | SSM | CD** |
| 4 | Prolonged cough* | CXR‡ | XP | CD** |
| 5 | Any TB Symptom+ | SSM | CD§ | |
| 6 | Any TB Symptom+ | XP | CD§ | |
| 7 | Any TB Symptom+ | SSM | CD§ | |
| 8 | Any TB Symptom+ | CXR‡ | XP | CD§ |
| 9 | CXR abnormality suggestive of TB | CXR‡ | SSM | CD§ |
| 10 | CXR abnormality suggestive of TB | XP | CD§ | |
| 11 | Any CXR abnormality | SSM | CD§ | |
| 12 | Any CXR abnormality | XP | CD§ | |
SSM = Sputum smear microscopy; XP = Xpert MTB/RIF; TB = tuberculosis; CXR = chest X-ray.
CD = clinical diagnosis, which may in addition to clinical judgment include antibiotic trial and/or CXR for TB abnormalities.
*Cough for 2-3 weeks or longer †Any one out of 4-7 symptoms suggestive of TB.
§We assume that the proportion of persons who receive a clinical diagnosis depends on the negative predictive value of the prior algorithm, as explained in the Methods.
‡Any CXR abnormality.
**All persons with a negative first confirmatory test receive a clinical diagnosis.