The Health Service Executive has confirmed that around 400 women received CervicalCheck letters with incorrect information in recent days, due to an issue at CervicalCheck that did not involve Quest Diagnostics.
As a result, all of the 870 women got the same letter stating that their HPV status remained negative, when around half should have received a different letter notifying them that their HPV status remained positive.
The letters were issued to clarify the delays in results being issued.
In around half of the cases, the letter said that the woman's HPV test result remained unchanged from their original smear test and remained HPV negative.
The latest problem is due to the fact that the notification system is not automated and there is a manual workaround.
The 400 women are part of the known group of 870 women who did not get their original test results and whose GPs were also not notified.
The HSE has said that all of the 400 women who were HPV positive would have known this from their previous test and would be treated accordingly.
The issue was reported in today's Irish Times after the newspaper said it was contacted by one of the women who had received one of the letters containing the incorrect information.
The HSE has apologised for the error and any confusion or distress it may have caused.
It said it would be writing to the women involved as a priority, to clear up any confusion they may have.
The HSE also said that any woman who has questions or concerns can email it at email@example.com or by phone at 01-8659392.