The Kimberley's peak Aboriginal health body says an investigation has revealed contamination as the likely cause of 55 false positive COVID cases that saw two major remote communities locked down.
Bidyadanga and Beagle Bay were locked down after recording 55 positive cases in February, as Western Australia's COVID outbreak began in earnest.
The positives prompted a serious and quick response from local health authorities, who swooped on the communities and completed contact tracing and additional testing.
But additional testing saw the cases reclassified as false positives, with a number of residents suffering other respiratory infections like the flu and rhinovirus at the time of testing.
Kimberley Aboriginal Medical Services (KAMS) launched an investigation, with additional support from the Kirby Institute, which has revealed contamination as the most likely cause for the false positives.
"We can't confirm this, we probably never will, but potentially out of a cracked cartridge," KAMS medical director Dr Lorraine Anderson said.
"It wasn't contamination with COVID-19, it was contamination with what's called amplicon which is the stuff that's in the liquid and the cartridge that goes in the machine."
'Back on track'
Researchers have previously raised the issue of amplicon residue "masquerading" as COVID-19 in PCR resting machines, and the need for decontamination strategies.
"We're thinking that through a process of elimination it's sounding as though that's probably the reason," Dr Anderson said.
"It sounds as though that's happened in a few remote clinics across Australia."
KAMS has also deep cleaned all its clinics as a precaution.
"We've got the people who have been involved in that point of care testing roll out to come through and double-check that.
"We think we're all back on track."
There are currently 243 cases in the Kimberley, while Western Australia has recorded 961,570 cases since the COVID-19 pandemic began.