The insurance industry made $2.2 billion in profits on medical malpractice coverage between 1975 and 1985, the General Accounting Office concluded in a report released yesterday, prompting the heads of two House panels to question why a "crisis" exists in malpractice insurance.

Rep. James Florio (D-N.J.), whose subcommittee is investigating the liability crisis, said the GAO report raised serious questions about assertions that "lawsuits and excessive court awards are making medical practice uninsurable."

The report was done at the request of Florio and Rep. Henry Waxman (D-Calif.), chairman of the subcommittee on health and the environment, which has jurisdiction over medical malpractice. "While doctors were leaving or cutting back on their practices and patients were being left without care, the insurance companies were prospering," said Waxman.

The insurance industry immediately denounced the report. "Averaging profits over a decade is like averaging the outdoor temperature over a year; it doesn't tell you a thing," said Marc Rosenberg, a spokesman for the Insurance Information Institute, a trade group. "The losses that occurred in 1983-1984 and led to the changes in premiums in 1985 are masked in a 10-year average," he said.

The GAO calculated that the entire property/casualty industry had profits of $81 billion during the decade, while the industry puts the figure at $54 billion. Acknowledging that the industry used a different accounting system resulting in smaller profits, the government watchdog observed, "Even the lower estimate by the industry shows that the industry's average rate of return on net worth has not been out of line with those of other industries."

The Insurance Services Office, which suggests rates for carriers, disagreed. Spokeswoman June Bruce said insurers had an 11 percent rate of return at a time when banks had a 12.7 percent return and the Fortune 500 enjoyed a 13.2 percent return.

"This study paints a picture of a very profitable medical malpractice insurance industry -- for the nation as a whole," Waxman continued.

"While there may well be serious problems in individual states, or for specific specialities such as obstetrics and gynecology... the overall financial picture for malpractice insurers nationwide looks quite healthy."

A decade ago there were 10 or 12 commercial insurance companies writing medical malpractice insurance nationwide.

Today there are just three, according to Rosenberg. Three dozen physician-owned companies have moved into the market.

"If it is so profitable, why isn't anyone breaking down the door trying to write medical malpractice?" asked Ronald S. Gass, senior counsel to the American Insurance Association. He said that by January 1988, commercial insurance companies will have abandoned the market in Florida.

That state is often cited as one of those most affected by the crisis. Since last July, when St. Paul Fire and Marine Insurance Co. raised rates 43 percent, more than 57 hospitals in Florida have barred emergency patients because of a shortage of specialists. In Dade County (Miami), where the average jury award last year was $250,000, St. Paul reported receiving 32 claims for every 100 insured doctors, nearly twice the national average. St. Paul will leave the state at the end of the year.