A forensic scientist has confirmed there was an error in her notes relating to samples taken from Auckland woman Blessie Gotingco, but that did not mean her results were compromised.
A 28-year-old man, who has name suppression, has denied charges of raping and murdering Mrs Gotingco, and is representing himself after dismissing his lawyer.
ESR scientist Fiona Matheson confirmed that she mistakenly moved the wrong sample to another lab.
The amicus lawyer Kevin Brosnahan is assisting the court and asked how the court could then be confident in any of her results.
Ms Matheson said that was taking the error too far.
Earlier, Ms Matheson dismissed concerns that DNA samples taken from Mrs Gotingco and the man accused of killing her could have been contaminated while in transit.
She had been questioned about swabs taken from the body of Mrs Gotingco during the post-mortem examination.
Ms Matheson confirmed that ESR best practice was to remove the ends of the swabs which allowed the them to dry out and avoid being ruined by mould.
That was not done by hospital staff, so she left the swabs out to dry.
Mr Brosnahan asked if that could allow the swabs to become contaminated.
Ms Matheson said that was a theoretical possibility but she did not believe it had happened.
She also demonstrated how swabs were sealed in plastic tubes and sealed inside envelopes.
Ms Matheson said the envelopes were taped and signed.
The accused opposed the demonstration but Justice Brewer said the Crown should be allowed to answer the questions raised in cross-examination.
The court had earlier heard police had to transport samples from the body of Mrs Gotingco and the accused in the same police car because not enough vehicles were available.
Samples from the body of the 56-year-old Auckland woman were held in the boot of the car while those from the accused were transported in the front seat.
Ms Matheson told the court today there should be no contamination problem provided the samples were properly packaged and sealed.
Ms Matheson confirmed ESR scientists carried out further testing on samples taken from Mrs Gotingco after a pre-trial hearing, days before the trial was due to get underway.
Mr Brosnahan described that testing as last minute.
The scientist also confirmed 400 pages of evidence were released to the defence in the week before the trial began.