According to the former Labour leader, Gordon Brown, patients north of the border would be "at risk" in the event of a Yes vote.
Brown said: "I call on the SNP to tell the truth about the benefits we receive from direct links with England in healthcare."
However the Labour politicians attempt to scare patients who benefit from cross-border collaboration has been condemned by the Scottish Government.
A spokeswoman for the SNP administration said: "NHS Blood and Transplant, which co-ordinates organ donation across the UK, has already confirmed in writing that independence would not lead to any change in these arrangements."
The claims from Brown were disproven in March this year when a letter from the NHS Blood and Transplant (NHSBT) service, which deals with the transport of vital organs across the country, stated that it expects cross-border healthcare systems to stay in place after a Yes vote in September.