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Task force studying anti-core as surrogate AIDS test.

Hoping to reduce the chances of more blood product recalls and withdrawals due to suspected AIDS-transmitted transfusions, a Federal task force is now studying the technical issues involved in using anti-core testing routinely to detect the presence of infection in all source plasma going into fractionation.

The task force, headed by Michael Rodell, Ph.D., of Armour Pharmaceuticals, includes representatives of all the nation's major blood organizations as well as manufacturers and the Food and Drug Administration. Its goal is not to recommend regulatory action, but rather to help assess whether applying the anti-core test regularly for certain blood products "is something we can agree is appropriate and reasonable until such time as a regulation should be written," noted Dr. Dennis Donohue, director of the FDA's Division of Blood and Blood Products.

Dr. donohue himself offered the anti-core test proposal for debate at the conclusion of a two-day FDA-sponsored workshop in mid-December that brought together nearly 100 researchers from across the country and the FDA's Blood Products Advisory Committee. The scientists heard a dozen optimistic presentations by clues or definitive factors indicating acquired immune deficiency syndrome's presence in blood.

While much of the research presented was promising, the unmistakable marker that lends itself to a basic laboratory test is still beyond researchers' immediate grasp. The blood banking community, therefore, remains in a hopeful but delicate position, knowing that the odds of transmitting the disease through transfusions are extremely low, but realizing that the public's jitters can be easily aroused and that resources can be depleted quickly through recalls.

For nearly a year, the blood banking community has relied on an agressive public campaign to have donors in the four high-risk groups (homosexuals or bisexuals with many partners, intravenous drug abusers, hemophiliacs, and Haitians) voluntarily refrain from giving blood. Because AIDS has a two-year incubation period, the campaign's effectiveness won't be known for another year. Meanwhile, still lingering are the risks to patients and the blood supply, especially pooled plasma, from donors who give untruthful personal histories.

Thus, Dr. Donohue's suggestion for a compromise interim measure: "I'm proposing the use of a lab test rather than simply asking someone if he is homosexual or not."

More specifically, he said, "It seems to me what we are looking for at the moment is something that will define whether an individual has been exposed to infectious diseases." He noted that while there are a number of tests that accomplish this, the anti-core test accurately determines exposure to infectious disease with 85 to 90 per cent accuracy.

"I wonder whether that application, combined with heat treatment [of the product], doesn]t have the potential for giving us as much assurance as is possible today that Factor VIII should be transfused," he conjectured. And if so, "might that not form the basis for accepting whatever residual risk there is with Factor VIII and put us in a position to protect the [blood] supply by eliminating the possibility of recalls and withdrawals, in contrast to the situation that has occurred since July."

The FDA has undertaken numerous blood product recalls over the last eight months. One case alone involved 15 lots of AHF (anti-hemophilic factor), which converts into 500 patient treatment years. The donor in that case had been giving for a long period before being diagnosed as having ADIS.

Dr. Donohue suggested that the process whereby plasma is collected lends itself to centralized procedures where testing could be done in five or six fractionation locations, enhancing efficiency and creating a focus on responsibility. While he didn't mean to "turn away from whole blood," he continued, the fact that there are 7,000 facilities involved makes that isue "significantly different" from the plasma fractionation process.

Advisory committee members generally favored the concept. Dr. James Mosely of the California Department of Health Services called it "a prudent measure. It may increase costs, but the cost may be considerably less than those--both financial and in resources--associated with a single recall."

Dr. James White of the University of Minnesota School of Medicine noted that "what we're hearing indicates that AIDS itself is likely an infectious process" and that makes it "resonable to choose to look for an elevation in the core antigen. . . . Given the pressure the bureau may be under, this [anti-core testing] may be appropriate. . . ."

And Dr. Dorothea Zucker-Franklin of the New York University Medical Center, referring to the group's moral responsibility, said she would "have a hard time figuring out how not to agree with Dr. Donohue's proposal."

Reservations, however, were voiced by many workshop participants, some of whom cited costs and the emotional trauma for those individuals who may be rejected as donors. "Since we're possibly on the threshold of a whole series of new tests that may be better, why not adopt a limited wait-and-see position?" one blood banker suggested.

Supply was also a major concern among several spokesmen who noted that the core test would eliminate 5 to 6 per cent of the volunter donor base of 500,000 people. Herbert Perkins of San Francisco's Irwin Memorial Blood Bank emphasized that the rejection rate would be highest for the elderly, "the repeat donors we have most reliance on." Rejections would similarly be high for Asians, blacks, and Mexican Americans, "and we need these people to donate because we need their blood types for recipients from their own ethnic group," he pointed out.

But most comments--and the strongest--concerned the apparent dual system and standard that might evolve. Johanna Pindych of the Greater New York Blood Program warned of the proposal's implications for the volunteer donor sector. It would seem, she said, that "if it's good to do, then it's good to do for all donations. . . . Some of us in the volunteer sector don't think you can separate the industry into two kinds of donor pools."

Another participant felt that "once you decide that a surrogate test should be used and you then choose one, you need to apply it to all [donations]." To do otherwise, he said, creates "an ethical dilemma."

The proposition, in effect, "is not that anti-core be used as a surrogate for AIDS but as a surrogate for truthful history," a third speaker added. "The heart of the problem in the voluntary area is that . . . some closet gays are getting by because they don't want to disclose their affiliation with the high-risk group. If you accept that we would be using this [test] as a truth test for paid donors, then it's only an extrapolation that it be requested for all persons who may be hiding the truth in their health history. And pressure will follow to extend it to all."

In defense of selective surrogate testing, Dr. Mosley pointed out that the "justification for applying the test to one group exists in the risk of the product." He classified three types: average-risk products, safe products (i.e., pooled products that can be treated), and high-risk products (pooled products that can't be treated). Referring to statistics presented earlier in the conference, he pointed out that there is a demonstrated higher risk of AIDS in patients who receive high-risk products. Moreover, he said, "I don't have much doubt that among the anti-core positives there are far more people we would rather not have donate" than there are among the anti-core negatives.

"If that is generally true, what use should we make of it?" he asked rhetorically. "Well, for that limited group, the paid plasmapheresis donors--and not the recovered plasma, which comes from the lower-risk donor--the public and industry would benefit by eliminating risks through a very simple [anti-core] test, one my lab has found by radioimmunoassay to produce very few false positives."

Advisory committee acting chairman Dr. William V. Miller, director of the American Red Cross Blood Services' Missouri-Illinois Region, wrapped up the discussion with a personal observation. "I think it is impossible to separate voluntarily donated plasma that goes into fractionation from the commercially donated plasma that goes into fractionation because you end up with a high-risk product both ways. And I think that substantially complicates the issue."

That will be just one of many questions the task force will have to tackle. At this writing, the panel had not yet conducted its first meeting, and so had no timetable for completing its work.
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Publication:Medical Laboratory Observer
Date:Feb 1, 1984
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