Blacks who need kidney transplants wait for them almost twice as long as whites do: 13.9 months on average compared with 7.6 months, according to a study by Richard P. Kusserow, inspector general of the Department of Health and Human Services.

The disparity cannot be explained by differences in "blood type, age, immunological and locational factors," because it is still substantial after these factors are considered, Kusserow said.

Although Medicare pays much of the cost of transplants for most people -- including the young -- through a special program, many poor blacks may lack funds to pay the remaining costs and may be considered less satisfactory candidates, the study said. Kusserow raised the possibility that racial prejudice is a factor.

He said the American Medical Association Council on Ethics and Judicial Affairs noted a possible "subconscious bias" against blacks in selection of kidney recipients and has said, "It is unlikely that medical differences account for all of the disparities."

Secretary of Health and Human Services Louis W. Sullivan said, "I am calling on the health divisions of this department to vigorously investigate the causes of this differential and to look for solutions to the problem that can be implemented quickly and effectively. We in government need to do what we can to assure that the organ transplantation system works well for minority and non-minority Americans alike."

Another problem is that kidney transplant centers within each of the nation's 72 organ procurement regions tend to keep any kidneys they procure for themselves or for other transplant centers within their region, exhibiting a sense of "local ownership" that reduces the number of available kidneys. This is in accord with a "local use" policy that allows the 250 transplant centers "to retain almost all of the organs they have retrieved," transporting them to other centers or regions "only at their own will."

"Only about 22 percent of all kidneys retrieved are distributed nationally," Kusserow said. "Most organs that are procured within a service area never leave that area."

As a result, some people who are high on a waiting list at one center must wait a long time for a kidney while others much farther down a list elsewhere get them quickly because that center has obtained more usable kidneys. At some transplant centers, patients had to wait 18 months or more while at others the wait was under 6 months, Kusserow said.

He recommended as a first step that a single waiting list be established within each organ transplant region, and that all organs available in that region be distributed on a first-come, first-served basis.

Research projects could determine whether a single list could later be compiled to cover several regions.

Kusserow also proposed additional studies on the reasons for racial disparities in kidney waiting times and treatment.

Kusserow's report said there were 8,932 kidney transplants in 1988.