Updated

More than 50 cancer patients will have to wait an agonizing three months to find out whether they have been infected with HIV, after a New South Wales clinic used one needle on patients for two months.

The bungle occurred when a newly employed nurse mistakenly believed the Accu-Chek Multiclix, a device used to check blood sugar levels, automatically changed needles.

Dr. Michael Jones, chairman of the private radiology company PRP Diagnostic Imaging which runs the Gosford clinic, said the nurse didn't realize she had to change the needle manually for each new patient.

Instead, the needle was left unchanged between November 28 and January 28, and used on 53 patients and two staff members.

The patients had visited the clinic to undertake a positron emission tomography (PET) scan for cancer detection, which requires them to have their blood sugar levels tested.

The error was discovered when a staff member with diabetes asked the nurse to perform the test on her and discovered the incorrect usage, Dr. Jones said.

'Unfortunately, the device that we've used, there was a misunderstanding about the suitability and operation of the pin-prick device, the result of which was that the same needle was used repeatedly on several people over two months,' he told AAP.

'The moment we found out, we withdrew it from service.'

He said the clinic had now switched to single-use devices where such an error couldn't happen.

Patients were this week sent letters of apology instructing them to undergo blood testing for HIV and hepatitis B and C.

Dr. Jones said advice sought from an infectious disease specialist indicated the risk of infection was 'low or very low'.

He said the clinic was 'extremely disappointed' by the incident and the nurse involved was 'shattered'.

The nurse, staff and cancer patients involved would be offered support and counseling, he said.

'We're deeply apologetic that this episode in their journey is just another problem for them to cope with,' he said.

The bungle was the result of 'misunderstanding at multiple levels' about the machine's use.

A mother of three diagnosed with esophageal cancer in April was among the patients tested with the needle to see whether her tumor had shrunk.

'When I opened the letter I felt like I wanted to fall on the floor, I was sick,' the 54-year-old told News Ltd.

'These are some of the sickest, most vulnerable patients, whose immune system is already compromised, and we have to be tested for HIV and hepatitis - and then wait for three months to do another test?'