Hundreds of semen samples taken as evidence of sex crimes were not tested for DNA by Queensland's forensics lab, an inquiry into its processes has heard.
The inquiry before Walter Sofronoff KC is examining collection, testing and analysis of material, and processes at Queensland Health's Forensic and Scientific Services, following revelations of a decision not to test crime scene samples that contained extremely small amounts of DNA.
For eight years, most semen samples would only progress to the DNA testing phase if sperm could be seen under a microscope, Counsel Assisting Susan Hedge told the court.
However, scientists could use their discretion to process samples in which sperm was not seen.
A scientist at the lab raised the alarm with management, when a semen sample they tested yielded a strong DNA profile, despite sperm failing to show when the sample was examined under a microscope.
Despite being alerted of the discrepancy in March 2016, no changes to workflow were made until August that year.
The inquiry heard the laboratory reviewed 738 samples, processed between August 2016 and March 2017, where sperm was not observed under the microscope.
Upon further testing, sperm was found on 147 samples.
Under the previous workflow, 29 of those would not have been tested for DNA.
"The missing of a sample like that, meaning there's no further testing of the sample, might have a significant impact on a case," Ms Hedge said.
Mr Sofronoff estimated about 400 samples "went through to the keeper", while the old workflow was in place.
He criticised how long it took the lab to change the workflow.
"For eight months they just continued with a process that was leading to error," Mr Sofronoff said.
"That doesn't sound very scientific."
'It is freaking me out'
The inquiry was shown an email sent to colleagues by scientist Amanda Reeves.
"I can't understand why there isn't more urgency around this. It is freaking me out," Ms Reeves wrote.
"I dare not say anything though, this is how I got yelled at the last time."
The inquiry heard the lab has not counted how many semen samples might not have been processed under the old workflow.
"Whatever has been missed has been missed, and they've never looked at how many may have been missed," Mr Sofronoff said.
Microscopy expert Clint Cochrane compiled a report on the testing discrepancies.
He gave evidence that out of the 29 samples that would have been "missed", according to the lab's review, only one would have been "heavily affected" by the absence of DNA testing.
"There were other results in the sexual assault investigation kit that would have obtained the same information," Mr Cochrane said.
The inquiry continues.
