Target prioritization and strategy selection for active case-finding of pulmonary tuberculosis: a tool to support country-level project planning

Table 2 Diagnostic algorithms predefined for the model

Strategy	Description	First screening	Second screening	Diagnostic test	Maximum proportional yield*	Example in Figure2(d) condition***
1	Basic routine programme model	Symptom	–	Microscopy	PYss	24%
2	Strategy 1 + smear-negative diagnosis with X-ray	Symptom	–	Microscopy X-ray	PYss + part** PYsc	24–40%
3	X-ray + symptom screening	Symptom X-ray	–	Microscopy	PYss+PYxs+part** (PYsc+PYxc)	60%–100%
4	Prevalence survey model	Symptom X-ray	–	Microscopy Culture	PYss+PYsc+PYxs+PYxs	100%
5	Xpert in Strategy 4	Symptom X-ray	–	Xpert	PYss+PYsc+PYxs+PYxs	100%
6	Restrictive screening + Xpert	Symptom	X-ray	Xpert	PYss+PYsc	40%

* PY: Proportional yield (a proportion of prevalent TB cases by symptomatic and smear statuses). Please see Table 1.
** A diagnostic sensitivity of smear-negative TB can vary depending on the programmatic setup.
*** A maximum proportion of TB cases that can be diagnosed.

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