Operational Handbooks

3.6 Multidisease testing considerations

Health needs are diverse, and programmes are expected to provide a range of diagnostics to assist health workers in managing patients as effectively and efficiently as possible. The diagnosis of TB often begins with assessing symptoms; this is not specific to TB, given that cough and fever overlap with COVID-19 and other respiratory infections. Additionally, people with TB may also have HIV, and services for both diseases are usually provided at the same levels of care.

3.4 Concurrent testing to improve case detection in children and in people (of all ages) living with HIV

The use of an mWRD as the initial test to diagnose TB greatly increases the sensitivity of the diagnostic process compared with the use of sputum smear microscopy (57). However, certain subpopulations will not fully benefit from the high sensitivity of the molecular tests. For example, people living with HIV, especially those who are seriously ill, are known to have difficulties producing sputum; similarly, children, especially those aged below 5 years, often cannot easily produce sputum.

3.2 Pretest probability and test accuracy considerations

The predictive values of a test vary depending on the prevalence of TB in the population being tested. The prevalence of TB in a country is best estimated through a national TB prevalence survey. Countries should conduct prevalence surveys about every 10 years. If a survey has not been conducted recently, WHO provides estimates of prevalence in its annual global TB report (2). These estimates are based on the number of notified TB cases submitted each year by Member States.