The North Western Health Board is to contract out all its cervical smear tests - 12,000 annually - to Altnagelvin Hospital, Derry, as waiting lists for test results grow.
The move comes as demand for cervical screening in the north-west jumped by a third in six years, with the board admitting that waiting times were "less than satisfactory".
A NWHB spokeswoman said discussions were at an advanced stage with Altnagelvin, and it was expected the contract would take effect from next month.
The board was commenting after it emerged that a woman from Buncrana, Co Donegal, who is recovering from breast cancer following a mastectomy two years ago, and whose smear test was deemed an emergency in May, is still awaiting her results.
"I'm getting very anxious at this stage, and I'm very, very angry because as far as I'm concerned anyone with a history of cancer should be given priority," she said.
When contacted, the NWHB said it was prohibited from commenting on individual cases. However, it said currently all its cervical smear tests were processed by Sligo General Hospital. "The demand for this service has increased substantially in recent years, with a 30 per cent increase in the last six years," said the spokeswoman.
"The processing capacity within the laboratory at Sligo General Hospital is approximately 7,000 tests per annum, with the current complement of 2.5 whole-time-equivalent medical scientists engaged in cytology screening."
The NWHB also blamed the national shortage of trained technologists in the field, complicated by the extended training required for newly-qualified staff.
"In addition, the reporting of tests is subject to the workload constraints of the two consultant histopathologists in the hospital.
"Due to the general increase in laboratory activity, there has been a build-up of cytology tests awaiting reporting by the consultants, who have had to prioritise the more urgent cases in all areas."
The board said it had sought to address the test waiting times through a number of measures.
"A service agreement with Altnagelvin Hospital, Derry, had been in place for some time, and an agreement has also been made with a laboratory in London for a backlog of unreported cases. This backlog is expected to be cleared within four weeks."
The spokeswoman explained that all the board's efforts were "interim in nature" pending the roll-out of a national screening programme scheduled for 2006.
"We continue, in the interim, to have demand that we do not have the capacity to meet. We continue to put in place contracts with external hospitals like London when that is possible. However, all of it is less than satisfactory from the patient's point of view."