DNA testing has provided the biggest revolution in the identification of criminals since the adoption of fingerprinting in the early part of last century. Still, the technology has limitations. Most genetic tests take 24-72 hours but the time taken for DNA to go from crime scene to identification can span as long as 14 days. By the time that the results are back, the suspects often have been released. A newly developed test could make checking DNA from people arrested for crimes against DNA samples from crime scenes stored in forensics databases almost as easy as matching fingerprints.

To increase the speed of forensic DNA testing, scientists from the University of Arizona and the UK's Forensic Science Service built a chip that can copy and analyze DNA samples taken from a cotton swab. Forensic technicians can collect DNA from suspects by swabbing their mouth, mixing the sample with a few chemicals, and warming it up. The DNA-testing-lab-on-a-chip does the rest. The entire process takes only four hours at present but the research team is already optimizing it and reducing the cycle time down to two hours.

With the test, police could check on whether a person’s DNA matches that found at past crime scenes while suspects are still being processed and before a decision on whether to release them on bail has been made. Portable DNA testing could also be used in disasters such as earthquakes to identify victims the researchers said.

The researchers also envisage a time in the near future when DNA could be identified by such small instruments using the technology that testing could be done in a police car or by immigration officials as a border with the goal of proving identification, thereby repelling terrorists and other criminals.

The rapid DNA testing technology is being tested in police labs in the U.S. and Europe and could be commercialized in 18 months.

A report on the fast forensic test appears in the ACS journal Analytical Chemistry.