The nation's medical system still furnishes better health care to whites than to nonwhites, despite "important gains" in the health of nonwhites over the past 20 years, the Congressional Budget Office has found.

It listed in a recent report four main reasons: high costs combined with low incomes, non-financial barriers such as discrimination or localized shortages of doctors, lack of follow-up care, and "too little emphasis on some conditions affecting nonwhites."

Among the ways to improve health care for nonwhites, the report said, are "more vigorous" affirmative action programs in medical schools.

The U.S. Supreme Court in October heard oral arguments in the case of Allan Bakke, a white who sued the University of California, claiming an affirmative action program kept him out of its Davis medical school.

The report, requested by two members of the Congressional Black Caucus, Reps. Parren J. Mitchell (D-Md.) and Louis Stokes (D-Ohio), said experience with present federal programs indicates that just pumping in more federal money may perpetuate the differences in care.

Government health programs that provide health services directly serve nonwhites more effectively than programs which give government money to private health care facilities, the report said.

And it noted that one remedy would be for the government to supply health care directly where the private sector falls short.

Statistics cited by the report to illustrate the disparity included a 70 per cent higher infant mortality rate for nonwhites, 50 per cent more bed disability days, a life expectancy six years shorter, and a greater chance of suffering from specific ailments which proper health care would improve.

The report said nonwhites are four times likelier than whites to die of heart disease and chronic kidney failure, three times likelier to die of high blood pressure, and five times likelier to die of tuberculosis. Nonwhites chances of death from diabetes are twice that of whites, the report said. It added that nonwhites are seven times more likely to be victims of homicide.

Black women are five times more likely to die of complications in child birth than whites, a fact which combined with the higher infant mortality rate "suggests a continuing lack of prenatal care," the report said.

It cited "discrimination" in the Medicaid program, the main provider of health care for the poor. In 1969, it said, Medicaid paid an average of $213 in health care costs for each nonwhite beneficiary, compared to $375 for each white beneficiary - 75 per cent more.

Physicians in inner city areas are most likely to refuse to serve Medicaid patients, the report said. And it noted that the southern states, which tend to have lower Medicaid benefits, also have a high proportion of poor nonwhites.

Medicaid served 24.4 million beneficiaries in fiscal 1976, according to government figures, paying $15.5 billion in claims. Some $8.6 billion of that was federal money.

The report said the federal government could help in the short run by standardizing Medicaid benefit levels for all states - at an additional cost of roughly $10 billion to $11 billion in 1978.

It also said documented discrimination exists in nursing homes.

In keeping with the method of counting most commonly used in government programs, the report classified all persons of Hispanic heritage as white. Blacks, American Indians and Orientals were counted as nonwhites.