Screening risk populations and providing appropriate treatment are crucial to achieving the goal of reducing the burden of TB. International guidelines for TB Control in Prison Services recommend screening of all new inmates upon entry using symptom and Chest X-ray screening. Recent recommendations are listed below to which innovations in diagnostic imaging respond as operational and financial enablers:

"Screening all prisoners at entry with CXR is beneficial for identifying undiagnosed active TB using symptom screening.

Prisoners with abnormal CXR are then followed up with sputum examination

The strategy also reduces delays in the diagnosis of TB, reducing the time of exposure to other prisoners. In addition, it is a cost-effective measure for case detection.

The high sensitivity of screening through CXR compared to symptom-based assessment cannot be ignored.

It can be used together with a symptom questionnaire. This approach could be limited to prisons where TB, HIV, are highly prevalent.

TB control programs should prioritize these facilities to expedite TB diagnosis and treatment, thus reducing HIV-related TB morbidity and mortality.”

* Source: Guidelines for Control of Tuberculosis in Prisons TBCTA, USAID and ICRC; January 2009.

The limitations of screening on symptoms only are illustrated below.

Zambia TB prevalence survey, 2005 (Ayles et al 2009):
-35% of bacteriologically confirmed cases had no cough
-57% of bacteriologically confirmed cases did not fulfil "TB suspect" definition

Active case finding in risk groups

Passive: symptoms, microscopy & culture: 20-50 days
Active: symptoms, CXR & molecular test: 2.5 hours

Assuming 3% TB prevalence in high risk groups; this could be applicable for high risk populations such as PLWH, diabetics, mine workers, inmates, armed forces, refugee camps