The best way to reform the nation's health care system is to build on the current framework, not start over with a new one, House Majority Leader Richard A. Gephardt (D-Mo.) said yesterday.

Gephardt, testifying before a Senate committee, said the current system, in which 37 million Americans have no health insurance and which costs about 12 percent of the nation's gross national product, needs major reforms.

"I personally believe that it would be best to build on what we have, rather than starting anew with an entirely different system," he said.

To stem medical costs, which are rising faster than inflation, and to extend access to the system, various groups have been calling for top-to-bottom changes, including a nationalized health insurance system.

But the majority leader noted that changes in the mid-1980s in the way Medicare reimburses hospitals have slowed the growth of these costs, he noted, and recent physician payment reforms are expected to do the same for doctors' costs.

"I think we should use this experience and the successes we have gained over the years, in both the public and private sectors, as we develop a new national strategy to ensure access to health care for all Americans," he said.