A number of women who were given the all-clear after smear tests have been told the results were wrong, an NHS trust has said.
Seventeen women in Essex were wrongly told their results were normal, when in fact they had abnormalities.
They had been tested at a lab run jointly by Southend, Basildon and Thurrock Hospitals, and a private firm.
An spokesman for Basildon and Thurrock NHS Trust said 2,500 samples were being reviewed, and 900 had been done so far.
“We understand that this is a potentially worrying time for the women involved and would like to reassure all women covered by the locally provided cervical screening programme that this was an isolated incident,” the trust said in a statement.
The samples were reanalysed after issues were identified in the cervical screening lab service provided by Pathology First, the service jointly operated by the hospitals and Integrated Pathology Partnerships Limited.
An independent screening service was brought in to re-test the samples.
Of the 17 women who need further investigation, nine have been contacted for rescreening and eight have been referred for further tests.
Women whose re-analysed tests come out as negative will not be contacted, the trust said.