The truth about the status of the nation's blood supply is as much a casualty of the AIDS epidemic as any of the thousands of people who have died from the disease.

Because maintaining a safe and adequate blood supply is one of the most important priorities we face as a nation, it is time to set the record straight about the status of the blood that millions of people give or receive every year.

Ten years ago, AIDS was unknown to the medical community; it is difficult to imagine having a discussion of the health care system today without taking the epidemic into account. One observation about health care, however, is certain: The blood supply has undergone more intense public scrutiny than any other segment of the health care industry since AIDS was identified and efforts to curtail its spread were initiated.

Beginning in April 1985, the safety of the blood supply was achieved, to a large degree, by the use of tests to detect antibodies to the human immunodeficiency virus (HIV) and by expanded donor screening. According to a recent study by the Centers for Disease Control, there have been only 12 documented cases of AIDS contracted through contaminated blood since 1985, a period during which an estimated 20 million people received transfusions. A study published in the New England Journal of Medicine last year estimated the risk of contracting AIDS from blood as 1 in 153,000, based on national averages.

Even so, a public opinion poll conducted by the American Association of Blood Banks last year found that while two thirds of the nationwide random sample felt that the blood supply is safer today than it was five years ago, concerns remained. For example, 20 percent erroneously believed that AIDS could be contracted from blood donations; others said they thought AIDS would be a likely result of a blood transfusion.

The following are facts about the blood supply that every American should know: We depend on blood more than we realize. Without blood from the community supply, many medical and surgical procedures would not be possible, and lives of cancer, cardiac and organ transplant patients as well as seriously ill newborns would be lost. The American blood supply is constantly and thoroughly tested. Blood banks have added five additional screening tests that have been licensed by the Food and Drug Administration since 1985 to increase safety. Seven separate tests are conducted on each unit donated, including tests for AIDS, hepatitis and syphilis. In addition, each donor is asked multiple questions about behavior that would disqualify donations.

No medical procedure can be entirely free of risk. However, every scientific and medical development with the potential for increasing the safety of the blood supply is evaluated by scientists, and threats to the integrity of the blood supply are continually monitored. Research from the National Institutes of Health, information from the CDC and oversight by the FDA further support these efforts. Private industry also continues to focus on improving testing procedures and anticipating future needs.

Blood banking is one of the most highly regulated areas in health care today and is governed by multiple federal and state laws, rules, policies and regulations.

Every facility must be registered or licensed by the FDA and must adhere to these regulations plus additional FDA guidelines that are issued continuously. In addition, standards set by the American Association of Blood Banks are followed by community blood centers and hospital transfusion services through an inspection and accreditation program. Over and above these programs, blood banks may be inspected by state and municipal health agencies, the Health Care Financing Administration, the College of American Pathologists and the Joint Commission on the Accreditation of Healthcare Organizations. The blood supply depends on volunteers. The practice of paying people for their blood was largely phased out in the 1970s; blood that goes to hospitals for patient care comes exclusively from about 8 million volunteers. The U.S. does not always have an adequate supply of blood. While protecting it against infectious diseases is of paramount concern, maintaining an adequate supply of safe blood has become increasingly important as donors receive more scrutiny. While more than half of Americans are eligible to give blood, less than 10 percent actually do.

In addition, approximately 2 to 10 percent of whole units donated are discarded. Most discards are due to "false positive" test results caused by highly sensitive tests that erroneously indicate positive readings for some persons who are actually free of disease. This reflects precautions taken by blood banks and donor centers to ensure the safest blood supply possible. Sometimes there are alternatives to transfusions. A growing trend is the increasing use of autologous (or self) transfusions. The most widely used form is preoperative autologous donation, in which people donate their blood for use in their own elective surgery. Blood may also be recycled during some surgery using special equipment. These procedures help avoid any adverse reaction to the transfusion and provide further safeguards against the remote possibility of infection. There is no risk of AIDS or other infectious diseases when people donate blood. Sterilized needles that draw blood are never reused.

Combatting the fears and prejudices that discourage healthy, risk-free individuals from donating blood is the latest and greatest challenge to maintaining a safe and adequate national blood supply. The public needs to understand that efforts are ongoing to prevent unsafe donors from giving blood, to maintain strict testing procedures and to encourage the appropriate use of blood and its components.Toby L. Simon, a physician, is president of the Arlington-based American Association of Blood Banks. Second Opinion is a forum for points of view on health policy issues.