THE RED CROSS' Blood Service, which collects half of the nation's blood supply (about 6 million units) each year, has encountered many problems in the screening of donors and the collection, testing, labeling and distribution of its product.

In congressional hearings in 1990 and 1991, it was found that "various Red Cross collection centers (had) released infected blood, mixed up records, violated AIDS testing procedures and failed to deter infected or undesirable donors."Also, the Red Cross violated a 1988 agreement with the Food and Drug Administration (FDA) to implement standard operating procedures for its blood centers.

In May 1993, the FDA took the Red Cross to court, where it was decided that the Red Cross had to improve its blood service operations by specific deadlines or answer to a federal judge.

Since 1988, the Red Cross' Blood Service has had more than 3,000 blood safety violations, according to the FDA. At a center in Pennsylvania, blood contaminated with hepatitis B was released even after it was found to be contaminated, and blood components made from the blood of two HIV-positive donors were released from another center.

But the Red Cross is not alone when it comes to violating FDA blood safety regulations. Both the Life Source blood bank in the Chicago area and the Irwin Memorial Blood Center in San Francisco were cited by the FDA for testing blood improperly. Other blood banks have had similar problems.

The quality of the blood supply is lower than it could be, primarily because blood banks rely on a large pool of random donors.

In 1973, the U.S. government adopted the National Blood Policy, which was based on the hypothesis that "blood bought by for-profit firms necessarily transmitted more disease than blood donated to nonprofit blood banks." This policy changed the incentive for people to donate blood, but it did not address the real problem: a large pool of random, walk-in donors.

Although the blood supply has improved in quality, risks still exist - not only HIV and blood safety violations but also different strains of hepatitis and other pathogens.

Blood banks today will tell you that the blood supply is safer than ever, but except for improved testing and donor screening, the blood banks have not changed essentially. As long as public health policy is vulnerable to political pressure, consumers are at risk - which in these matters can prove fatal.