Scanners that can tell doctors within minutes what type of bugs are infecting patients are being developed by British scientists.

The machines - which could be ready for installation in surgeries by next year - will be able to spot the difference between major pathogens, such as those that cause meningitis and flu, almost instantly. As a result, hundreds of lives could be saved, say scientists at the Laboratory of the Government Chemist (LGC).

It sounds like the scanners used by Dr McCoy to give instant diagnoses in Star Trek. Nevertheless, such machines are close to development: researchers expect to complete an early prototype in a few weeks.

HyBeacon detectors will also be able to spot differences in patients' genetic make-up and help doctors prescribe drugs that are best-suited to them - thus preventing side-effects from inappropriate medicines.

'These machines will have all sorts of dramatic uses,' said Dr Paul Debenham, head of LGC. 'We should be able to use them in police stations to identify a person from his or her DNA in only a few minutes.' Dr Debenham is to reveal details of HyBeacon technology at the British Association for the Advancement of Science annual meeting in Leicester this week.

The scanners exploit the latest developments in gene technology. First, a saliva sample is taken, and its cells broken open using special chemicals. Then, DNA probes will be added to pinpoint the presence of genetic material from a particular bacteria or section of human tissue.

Finally, DNA amplification technology will be exploited to multiply these key pieces of DNA so that they can be spotted using light scanners. 'These techniques already exist, but are awkward to use,' said Richard Lewis, of Agile Technologies, which is collaborating on the project.

'Our breakthrough has been to find ways to do this simply. With our machines, it should be possible for a busy nurse to spot pathogenic DNA just from a drop of saliva. This is going to have a tremendous impact.'