DNA samples from criminal cases to be re-tested after HSA mistake

DNA samples in 87 criminal cases will be re-tested following the discovery of an error by the Health Sciences Authority (HSA)'s DNA profiling laboratory.

In a statement on Tuesday, the HSA said in August it was found that a reagent of 10 times higher than usual concentration was prepared and used as part of the DNA testing process.

The batch of reagent was used between October 2010 and August 2011, but the impact of the reagent used is small, HSA said.

The error rendered DNA tests less sensitive in detecting DNA profiles present in samples. The retesting is expected to yield additional DNA profiles in less than 5 per cent of the samples, HSA added.

To date, the first set of re-test results showed that only 2 out of 850 samples indicated additional reportable information, such as a DNA profile of another person not previously detected was obtained.

HSA assured that the previous tests will not cause any false positive results leading to wrongful identification of a person or inferring the presence of a person who was not there.

Separately, the Attorney-General's Chambers (AGC) released a statement and said it has requested re-testing from the 87 cases in which DNA test results may be relied upon by the Prosecution, the Defence of the courts.

DNA evidence by itself does not prove any person’s guilt, said Deputy Assistant Commissioner of Police Teo Chun Ching.

He added that DNA samples are considered in conjunction with other evidence such as CCTV footage, reconstruction of crime scenes and witness accounts to establish a case.

In light of the incident, the Ministry of Health has asked the board to appoint a committee to review the incident and recommend further follow-up action within HSA.

The re-testing is expected to be completed in March this year.