Patients' genetic suitability to different medicines could soon be tested with an electronic device.
A prototype of the handheld SNP (pronounced "snip") Doctor is already being tested by scientists at Imperial College London, and they predict it will be available to doctors within two years.
By placing a drop of saliva or cheek swab into the device it can analyse DNA and tell if a patient has the right genetic fit for a particular drug by searching for single nucleotide polymorphisms (SNPs) – single letter changes in the genetic code – that can affect an individual's response to medical treatment.
It is hoped that the technology will save some of the £460m currently spent by the NHS each year on treating 250,000 patients who are admitted to hospital suffering adverse reactions to prescribed drugs.
Being able to predict a bad response to a drug would allow doctors to tailor dosages and types of medication to individual patients.
Professor Chris Toumazou, who heads the Imperial College team, said: "Nothing can replace the expert advice your GP gives you. However, the Snip Doctor could provide another layer in the treatment process that could help GPs to personalise treatments according to the genetic requirements of each patient."