Mixing phlegm samples from multiple patients in “pooled tests” for tuberculosis could halve costs and help find millions of missing cases, according to a major new study.

While most advances in fighting TB come with a large price tag, the shift in strategy could dramatically boost access to diagnosis and save money, experts said.

TB is the deadliest single infection globally, killing around 1.3m people every year, despite being both preventable and curable.

The gold standard in diagnosis is rapid molecular testing, which detects genetic material from the bacteria causing TB in patient sputum samples within hours. But each sample needs a specialist diagnostic cartridge that costs around US$8, beyond the budget of many poorer countries even before recent aid cuts.

In a pooled test, samples from multiple individuals are tested in one cartridge.…