Scientists can now detect antibiotics in finger sweat

A fingerprint may soon be all a doctor needs to check whether tuberculosis patients are taking their antibiotics, with scientists at the University of Surrey successfully detecting the drugs in finger sweat — with almost the same accuracy as a blood test. Their results have been published in the International Journal of Antimicrobial Agents.

Curable tuberculosis (TB) is treated with antibiotics — but if patients don’t stick to their full course, the treatment might not work, leading to drug-resistant TB instead. Doctors need to check whether tuberculosis patients are taking their antibiotics, said Surrey’s Dr Katie Longman — “[but] for some patients, like babies, blood tests are not feasible or desirable.”

The scientists wanted to know whether they could tell how much medication the patient had taken by analysing their finger sweat, with co-author Longman noting that this would ease the time pressure on a busy health service and offer patients a more comfortable option. To do so, they recruited 10 TB patients at the University Medical Center Groningen (UMCG) in the Netherlands.

“It was very simple to collect our samples,” said UMCG’s Dr Onno Akkerman. “We asked patients to wash their hands, put on a nitrile glove to induce sweating, and then press their fingertips onto a paper square.

“Finger sweat can be collected without any specialist training. Unlike blood, it isn’t a biohazard, so can be transported and stored much more easily.”

The samples were shipped to The Surrey Ion Beam Centre and they were analysed using mass spectrometry, which breaks the sample down to see what it is made of. Antibiotics were detected in the finger sweat with 96% accuracy, while the metabolite produced by ingesting the drug showed up with 77% accuracy. The drug itself was present between one and four hours after ingestion, while the metabolised version showed up best after six hours.

“Up until now, blood tests have been the gold standard for detecting drugs in somebody’s system,” said study co-author Professor Melanie Bailey, from the University of Surrey.

“Now we can get results that are almost as accurate through the sweat in somebody’s fingerprint. That means we can monitor treatment for diseases like tuberculosis in a much less invasive way.”

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