Tony Blair has accused the Tory leader of "ruthlessly exploiting" the story of a pensioner whose shoulder operation was repeatedly cancelled.
Mr Blair told the conference the NHS had improved under Labour
The prime minister said to see Michael Howard using Margaret Dixon's case to run down the whole NHS "should make any decent...person turn away in disgust".
Mr Howard says her case highlights how government money is not getting through to "frontline" NHS services.
The Lib Dems say the case has become an unseemly row.
An angry Mr Blair told his party's Scottish Conference in Dundee the Tory leader was a serial opportunist who was trying to spread disillusion and cynicism.
And he appealed to voters to judge the NHS "with balance and perspective".
'Fight for Britain's future'
He said under Labour the NHS had 100,000 more nurses and doctors, 100 new hospital building programmes, half a million more operations a year and shorter waits.
He accused Mr Howard, as a cabinet member in the former Tory government, of helping to starve the NHS of resources.
"To see him take the case of someone in pain and use it to run down and denigrate the whole of our NHS, should make any decent right-thinking person turn away in disgust," Mr Blair said.
Mrs Dixon says she has had her operation cancelled seven times
He warned Labour supporters not to waiver at the next general election, widely tipped for 5 May, saying it would be a "fight for the future of Britain".
After the speech Conservative co-chairman Liam Fox said Mr Blair was not angry, but rattled "that people realise that his promise to 'save the NHS' was just talk".
And the Scottish National Party (SNP) said it was "grossly insulting" that the prime minister had used a Scottish Labour Party conference to talk about an English issue.
SNP leader Alex Salmond said: "This is yet another example of Blair coming north to make a speech for the south."
Mr Howard highlighted 69-year-old Mrs Dixon's case in the Commons on Wednesday, saying she was one of 67,000 people in England last year who had had operations cancelled.
She needs an operation to rebuild her shoulder, but it has been repeatedly postponed because she needs a high dependency unit (HDU) bed, also needed by critically ill patients.
The Tory leader told an audience in Birmingham on Friday that Mrs Dixon was not an isolated case.
He said: "She and her family, like everyone else, have paid their taxes and were promised by Mr Blair's government a better, more responsive NHS.
"This is what Mr Blair's NHS has done for Mrs Dixon - she is in constant pain and desperately needs an operation.
"When I raised this case in Parliament, I was accused of playing party politics. What is Parliament for if it is not to be a means to make ministers accountable for the services for which they are responsible?"
Labour accuse the Tories of being misleading about the case, while Mr Howard has asked the health secretary to withdraw comments made about his party's health policies.
Meanwhile Mrs Dixon has denied being used as a "political football".
"I certainly don't feel like I've been kicked. I wanted to highlight my particular problem in order that I could get the operation that I need," she said.
Arriving at his party's conference in Harrogate, Lib Dem leader Charles Kennedy said he did not want to get into personalised, negative campaigning because he thought it turned people off politics.
"I'm certainly not interested in getting into a 'Dutch auction' about who can be the most offensive about the other parties when it comes to the NHS," he said.
Instead he said he would talk "positively about constructive solutions" at the conference, because it would resonate with more voters.