Health labs in Dunedin have apologised to the Otago woman who had a mastectomy by mistake this year after her breast biopsy specimen was swapped with another.

Southern Community Laboratories pathologist and medical director Dr Peter Fitzgerald said he had felt very uncomfortable about the situation and had personally apologised to the woman who had the unnecessary mastectomy.

"I've been practising for not quite 20 years ... and I've never experienced this before."

He emphasised the "unfortunate" mistake could theoretically have been made with any specimen, not just breast.


"In many ways, the issues here equally apply to other specimens."

SCL improved its processes after the error occurred about three months ago to reduce the risk of the highly unusual mistake happening again, he said.

SCL was assisting Southern District Health Board's investigation into the mistake, which would take up to another fortnight to complete.

Dr Fitzgerald said the two samples had been taken from the women on the same day, at different times, by Dunedin Hospital radiologists, who correctly identified them and sent them to SCL for testing. SCL processed the specimens, giving them a unique lab number, and then sent them back to Dunedin Hospital to the SCL-operated lab there.

During the testing process in the hospital lab the specimens were inadvertently switched when they were transferred from their original container to another designed for the testing process.

"There's a potential for human error here, and this is what the problem is, I believe.

"As far as I know it's never happened before [to] us," he said.

As well as the unique lab number, specimens were labelled with patient names, National Health Index numbers, and accession numbers.


The lab worker was still working for SCL.

"Of course they've been spoken to; that goes without saying," he added.

DHB chief medical officer Dick Bunton said the DHB was leading the review in to the "patient diagnosis error" that occurred in the SCL lab. "We regret that the error occurred and have apologised for the harm caused."

A spokeswoman for the Health and Disability Commissioner's office yesterday said he was not investigating the issue.