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PHS issues guidelines on AIDS testing and follow-up for positives.

Anticipating that blood tests for detecting AIDS virus antibodies will be available this month, the Government has announced new recommendations for screening donated blood and plasma.

The Public Health Service's proposed approach covers blood testing procedures, the appropriateness of repeat tests, and steps for informing persons whose test results are positive. The agency counsels physicians on what medical measures to use and advice to give for patients who test positive. PHS's suggestions include ways to prevent further spread of the disease. It also stresses the need to maintain confidentiality.

"These Public Health Service recommendations are an important step forward in meeting our responsibility to the American people," said Health and Human Services Secretary Margaret Heckler during a recent press conference. Federal health officials estimate that less than 1 per cent of blood donors will have positive, confirmed results showing the presence of antibodies to HTLV-III, the virus believed to cause AIDS.

Heckler said it is particularly important to emphasize the uncertainty of the link between positive test results and the disease's course. "All our scientific evidence to date indicates that although many people may have been exposed to the AIDS virus, only a few will actually become ill," she pointed out.

At this writing, 7,981 people had been diagnosed as having AIDS, and 3,819 had died. Fifty-six cases had occurred in hemophiliacs, and 106 were transfusion-related.

Last April, PHS researchers isolated HTLV-III, developed a prototype antibody detection kit, and licensed five firms (Abbott Laboratories, Du Pont/Biotech, Electro-Nucleonics, Litton Bionetics, and Travenol-Genentech) to refine and mass-produce the test kits. By all accounts, the companies' efforts have proceeded smoothly, sticking to hoped-for deadlines and encountering no scientifc surprises.

A recent Journal of the American Medical Association report by researchers representing several institutions found that the test, in trials, had spotted HTLV-III antibodies in 82 per cent of 88 patients known to have AIDS. For another 16 per cent, results were borderline, while 2 per cent of AIDS patients did not have antibodies. Meanwhile, U per cent of 297 volunteer blood donors had the antibody, 6 per cent were borderline, and 93 per cent negative.

The report concluded that the test is "highly specific and sensitive for AIDS."

Still, while the Science might be encouraging to some, others find the imperfections in the test unsettling. At an American Blood Commission conference shortly after Secretary Heckler's public praise for the near-ready kit, opinion appeared split over the PHS recommendations for use and counseling.

Moreover, some within the gay community have urged a boycott of the test. For example, in a recent USA Today op-ed piece, Rodger McFarlane, executive director of the Gay Men's Health Crisis, said the test is "relatively cheap and fast," but also "appears to be dangerously unreliable."

Because most AIDS victims are gay, he claimed, the test will be used "as a marker for homosexuality. There are at present no legal protections guarding test results from health insurers, employers, or even the Government itself."

He added: "Nobody, least of all a gay man, should allow this test to be done on his or her blood except as part of a research program offering maximum protection of results, with the highest confidentiality." Noting also that no member of at-risk groups for AIDS should donate blood, McFarlane warned, "Until other tests are introduced, especially tests that confirm the presence of the virus itself, the antibody test alone can only serve to darken forever the life of anyone who tests positive."

At this writing, HHS expected to be clearing "more than one" of the test kits for commercial distribution by the end of February. The department also planned to mail to the nation's blood banks a set of instructions elaborating on the PHS recommendations. A separate special letter was to go out to all practicing physicians in the United States with suggestions on care and follow-up for those who may test positive.

The following are PHS-recommended procedures for the antibody test's administration:

* Initial screening. Persons accepted as donors should be informed that their blood or plasma will be tested for HTLV-III antibody. Persons not wishing to have their blood tested must refrain from donating. Donors should be told they will be notified if their test is positive and that they may be placed on the collection agency's donor deferral list, as is currently done for other infectious diseases. They should further be informed of other deferral lists to which positive donors' names may be added.

All blood or plasma should be tested for HTLV-III antibody by the enzyme-linked immunosorbent assay (ELISA) test. Any blood or plasam found positive on initial testing must not be transfused or manufactured into other products capable of transmitting infectious agents. When ELISA is used to screen populations in whom the prevalence of HTLV-III infections is low, the proportion of positive results that are falsely positive will be high. Therefore, the ELISA should be repeated on all seropositive specimens before the donor is notified. If the repeat ELISA test is negative, the specimen should be tested by another test.

* Other testing. Other tests have included immunofluorescence and radioimmunoprecipitation assays. But the most extensive experience has been with the Western blot technique, in which antibodies can be detected to HTLV-III proteins of specific molecular weights. Based on available data, the Western blot should be considered positive for antibody to HTLV-III if band p24 or gp41 is present alone or in combination with other bands.

* Notification of donors. If the repeat ELISA test is positive, or if other tests are positive, it is the collection facility's responsibility to insure that the donor is notified. the donor should be informed by an individual especially aware of the sensitivities involved.

Currently, the proportion of seropositive donors who have been infected with HTLV-III is unknown. Therefore it is important to emphasize to the donor that the positive result is a preliminary finding that may not represent a true infection. To determine the significance of a positive test, the donor should be referred to a physician for evaluation. The information should be gien in a way that insures the confidentiality of the test result and the donor's identity.

* Maintaining confidentiality. Physicians, laboratory and nursing personnel, and others should recognize the importance of maintaining confidentiality. Disclosure of positive test results for purposes other than medical or public health could lead to serious consequences for the individual. Screening procedures should be designed with safeguards to protect donors against unauthorized disclosure.

Donors should receive a clear explanation of how information about them will be handled. Facilities should consider contingency plans in the event that disclosure is sought through the legal process. Donor lists, where kept, should remain confidential. Whenever appropriate, as an additional safeguard, deferral lists should be general, without indication of the reason for inclusion.

* Medical evaluation. This might include ELISA testing of a follow-up serum specimen and Western blot testing if the specimen is positive. Persons who continue to show evidence of HTLV-III infection should be questioned about possible exposure to the virus or possible risk factors for AIDS in the individual or his/her sexual contacts.

They should be examined for signs of AIDS or related conditions, such as lymphadenopathy, oral candidiasis, Kaposi's sarcoma, and unexplained weight loss. Additional lab studies might include tests for other sexually transmitted diseases, tests of immune function, and, where available, tests for the presence of the virus, such as viral culture. Testing for antibodies to HTLV-III in the individual's sexual contacts may also be useful in establishing whether the test results truly represent infection.

* Recommendations for the individual. An individual judged most likely to have an HTLV-III infection should receive the following information and advice:

1. The prognosis for an individual over the long term is not known. However, data from studies conducted among homosexual men indicate that most persons will remain infected.

2. Although asymptomatic, these individuals may transmit HTLV-III to others. Regular medical evaluation and follow-up is advised, especially for those who develop signs or symptoms suggestive of AIDS.

3. Refrain from donating blood, plasma, body organs, other tissue, or sperm.

4. There is a risk of infecting others by sexual intercourse, sharing of needles, and, possibly, exposure to others' saliva through oral-genital contact or intimate kissing. The efficacy of condoms in preventing infection is unproved, but consistent use may reduce transmission.

5. Toothbrushes, razors, or other implements that could become contaminated with blood should not be shared.

6. Women with a seropositive test, or women whose sexual partner is seropositive, are themselves at increased risk of acquiring AIDS. If they become pregnant, their offspring are also at increased risk of acquiring AIDS.

7. After accidents resulting in bleeding, contaminated surfaces should be cleaned with household bleach diluted 1:10 in water.

8. Devices that have punctured the skin, such as hypodermic and acupuncture needles, should be steam sterilized by autoclave before reuse or safely discarded. Whenever possible, disposable products should be used.

9. When seeking medical or dental care for intercurrent illness, patients should report their antibody status to those responsible for their care so that appropriate evaluations can be done and precautions taken to prevent transmission to others.

10. Testing for HTLV-III antibody should be offered to persons who may have been infected as a result of their contact with seropositvie individuals (e.g., sexual partners, persons with whom needles have been shared, infants born to seropositive mothers).

HHS said recommendations will be revised as more knowledge and experience are gained with the new test.
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Publication:Medical Laboratory Observer
Date:Mar 1, 1985
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