The Health Service Executive has been instructed to reverse the decision to destroy blood samples taken from newborn babies, which are known as heel-prick tests.
Minister for Health James Reilly has said that more than one million samples should not be destroyed.
The Irish Heart Foundation said the cards could save the lives of extended family members of more than 1,000 young victims of Sudden Cardiac Death.
The decision to dispose of the samples had been made because of fears that their retention without consent breached data protection legislation.
The heel-prick tests are carried out on all babies shortly after birth to screen for genetic diseases.
Unclaimed samples taken from children between 1984 and 2002 were set to be destroyed shortly.
Samples taken before 1 July 2011 were deemed to be in breach of EU data protection legislation.
The minister has now instructed that an expert group discuss the matter and consider how the samples may be archived.
Taoiseach Enda Kenny has said it is important to find out how other countries have managed the situation.
Speaking on his way into Cabinet this morning, Mr Kenny said the samples could have real value in the future as a result of changes in technology and medical science.
The IHF, which launched the "Stop the Destruction Now" campaign, has welcomed the decision to retain the tests.
Its chief executive Barry Dempsey said: "The latest announcement means the estimated 1,400 families affected will not lose their last chance of a genetic diagnosis in the future nor will the last remaining DNA of their child be destroyed.
"Our charity welcomes the return to meaningful discussion through an expert group to protect these 1,400 samples and to ensure they are stored appropriately with proper consent.
"We look forward to open consultation to bring a positive resolution to this important issue."