MANY GPs continue to charge medical card holders up to €20 for routine blood tests, but face financial penalties for defying a warning to stop the practice.
The HSE has refunded individual patients the money after complaints - but then deducted the sum from the GPs' fees, amounting to several thousand euros in some cases.
However, the row is now threatening to escalate after the National Association of General Practitioners (NAGP) warned it may take a test case on behalf of doctors in the courts.
"This activity is not acceptable and the NAGP will ensure that it is challenged at the highest level," warned CEO Chris Goodey.
GPs, who have suffered a drop in State fees in recent years, insist the medical card contract they have with the HSE does not include providing free routine blood tests.
The doctors insist they are entitled to charge for "routine" blood tests which are part of monitoring diseases such as diabetes, arthritis and cancer.
However, they are not charging medical card patients for other blood tests, which would not be classed as routine, such as tests required for diagnosing an illness.
A HSE spokesperson said it was in "an ongoing dialogue with GPs on this matter".