Almost 4,000 smears screened at the Royal Berkshire Hospital between 1992 and 1994 have had to be re-checked after a woman was diagnosed with cervical cancer.
Six women with suspicious smears that were originally overlooked have been invited back for colpscopy examination (a visual check of the cervix with a microscope) and another 65 are being advised to have a repeat smear.
The incident is the latest to beset the troubled NHS cervical screening service. Last month,Warwickshire health authority announced that 18,000 smears were being re-checked.
Berkshire health authority said the review applied to the work of one screener whose work was first investigated in 1994 after concerns were raised about the screener's performance.
In that investigation one in ten of the smears reported to be negative by the screener were checked, in line with the guidelines which applied at the time.
The conclusion of the investigation was that the screener's performance was "within acceptable standards".
However, the screener transferred to other duties and never returned to screening.
After the case of cervical cancer came to light last month, the authority decided on a further review of the same screener's work which involved checking every negative smear she had passed, in line with the new guidelines applying today.
This disclosed the extra misread smears.
Dr Gary Bolger, acting director of public health, said: "We fully recognise that this is a worrying time for those women directly affected.
"Our objective has been to ensure they are followed up as quickly as possible and are given additional support and counselling if needed."
He said it was important that women retained confidence in the cervical screening programme. "I would like to reassure women that the laboratory at the Royal Berkshire Hospital is of a high standard. It meets all the nationally recommended targets for detecting abnormal smears and is overseen by a regional quality assurance programme."
A spokesman for the authority said that under new national quality control standards introduced this year, all smears are now subject to a rapid re-screen in which the findings of the primary screener are checked. Previously, only one in ten smears were re-screened.
In addition the spokesman said a new system to monitor the individual performance of screeners was now in place at the hospital.
The health authority said yesterday that only women who had had a smear test between January 1992 and January 1994 and had not had a smear test since were affected by the review.Reuse content