A REPORT published today (Thursday) by health chiefs has confirmed problems with staffing and paperwork at Cornwall's out-of-hours doctor service.
But the primary care trust (PCT) said Serco provision was fundamentally "safe and effective".
The NHS Cornwall and Isles of Scilly report, including an independent clinical review by David Colin-Thomè, cited the private company's recent clinical staffing challenges and issues with data handling.
Dr Colin-Thomè has made a number of recommendations which will be considered by the PCT board at its public meeting on Tuesday.
The board will also receive an update on the further work undertaken by Serco looking at its data recording processes. It has been show that computer records were changed without authorisation or sufficient justification, but in only 0.2 per cent of records between January and June of this year.
Serco has apologised and said it will work with the PCT to ensure consistent reporting in future.
The firm has been under fire since two independent investigations were launched into concerns raised in an inspection report by regulator the Care Qaulity Commission (CQC) earlier this year over alleged understaffing of duty GPs and its record-keeping in relation to un-met targets.
The PCT will now carry out independent validation of Serco's report which will be repeated in six months.
Steve Moore, chief executive of NHS Cornwall and Isles of Scilly, which commissions the service, said: "I was disappointed to learn that some of the data we received to measure performance was inaccurate although the number of inaccurate records was small.
"I am clear that Serco did not gain from these actions and they have issued a full apology to us.
"I am pleased to say that patient satisfaction with the service remains high and Serco is working constructively with us to address the issues raised by our review. We are confident that their aim is the same as ours, to provide a consistently high quality service to the people of Cornwall."