Good prescribing practices are important in tackling antibiotic resistance, and diagnostics are key to ensuring good practice. Knowing who not to treat is as important as knowing who to treat. The article reports on analyses by the Global Health Diagnostic Forum of the Bill & Melinda Gates Foundation to assess how many lives could be saved by better diagnostics for six major illnesses, including malaria and tuberculosis. The researchers assessed the technical issues associated with implementing the diagnostic tests in developing countries for three classes of laboratory infrastructure — none, minimal, or moderate to advanced.

They found that for acute lower respiratory infections, syphilis, gonorrhoea, chlamydia and TB, outcomes could be much improved if tests were sent to sites with minimal or no laboratory infrastructure. In these types of settings, the practicality of obtaining a specimen is important. For example, obtaining a blood sample correctly to test HIV viral load is almost impossible where there are no laboratory facilities. Using sputum to test for TB has similar issues because of the impracticability of the sample medium. Thus, new biomarkers might be needed to test for diseases with specimens different from those currently used. Combination tests that look for a range of infectious organisms in one sample would be useful in resource-poor settings.

The researchers also highlight the importance of taking into account cultural and social sensitivities when designing interventions – blood sampling is not always accepted in some regions of the world, for example.