Management of HIV/AIDS
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Types of HIV testing include population-based prevalence studies, patient-initiated screening, routine testing of high-risk individuals, diagnostic testing and mandatory testing, which involves blood donors and military recruits. Although occasional highly-publicized events will prompt mandatory testing of other populations, particularly health-care workers, this has not been found to be medically rational or cost-effective. A number of well-documented retrospective studies of HIV-infected surgeons have demonstrated the negligible risk of physician-to-patient transmission.14 To test health care workers would not only be burdensome but impractical, since constant "risk" and the 3 month window period would not detect cases sufficiently.

Some potential hazards of HIV testing do exist. Loss of confidentiality is a major concern, especially with respect to losing insurance coverage, although this has not been borne out among patients already insured. Past and potential discrimination suits have discouraged insurers to drop infected persons as clients. Anecdotally, however, some employers have been suspected of firing or laying off employees known to be HIV positive for other supposed reasons and insurance covered through the job was subsequently lost. Obtaining insurance after being determined to be HIV positive can be difficult, and the cost likely prohibitive.

Precautions for HIV Testing

  • Perform appropriate counseling before and after.
  • Maintain confidentiality.
  • Encourage partner notification (use anonymous notification, if necessary).
  • Make patient aware that total anonymity may prevent tracking infected persons.
  • In needle-stick exposure, unless source patient is under surgical sedation or is mentally incompetent, you should have consent to draw blood for HIV testing.
Anonymous testing is available in some states, but it limits tracking of infected persons. This is available since it removes a barrier from persons seeking their serological status. The information does help demographically as well, by providing knowledge of high prevalence areas and risk factors. Another approach recently designed to lower the testing barrier is the advent of home testing kits.15 The accuracy of these tests, which in general is quite high, must be confirmed with an approved blood test.

There are some ethical dilemmas involved in HIV testing. In addition to acknowledging the problem of getting diagnostic testing of an incompetent individual, drawing the blood from the source of a needlestick incident is not always clear-cut, even if the patient signed a face sheet waiver upon admission to the hospital allowing blood to be drawn under such circumstances. Therefore, except under emergency situations such as with the patient under surgical sedation or with mental status changes or incompetence, consent should be obtained.

Spouses and other sexual contacts at clear risk also pose a dilemma, particularly if the infected person is not willing to disclose his or her status to them. Although this disclosure should be encouraged, and legal precedents support notification one way or another, a partner notification program has been set up in at least one state to provide anonymous notification; sometimes this procedure will be acceptable to the infected person. In essence, a health department representative visits the contact (making visual confirmation) and notifies the person that he or she may have been exposed to someone with HIV. The source's name is not revealed and testing of the contact is encouraged. Although breaches in confidentiality may be superseded by public safety and welfare issues, it would probably be prudent from a legal standpoint to document your intentions to the source patient, acknowledging that he or she is aware of how the program works.

HIV Tests

Antibody testing
  • ELISA (screening)
  • Western Blot (confirmatory)
  • Saliva (antibody detection)
Antigen testing
  • HIV culture
  • HIV p24 antigen test
  • HIV PCR, DNA or RNA probe

HIV detection consists of antigen and antibody testing, with the latter representing the screening test that is routinely performed. The antibody test has a window period of 12 weeks, so anyone with a negative test who has high risk exposure within three months of having the test should be encouraged to have it repeated at least 90 days after that behavior or exposure.16 The antibody test consists of an ELISA test, which is an antigen-antibody interaction triggered by a light-stimulated enzymatic reaction. The false positive rate is low, but occurs enough to warrant that this test be repeated up to two additional times if it continues to read positive, or reactive. If a duplicate test is reactive, a confirmatory Western blot is done, which has nearly 100% specificity. A Western blot is not done initially for screening in light of its cost and labor intensity.

Positive ELISA results are not--and should not--be reported until confirmed by the Western blot. Testing is not pursued beyond a nonreactive ELISA, whether it comes on the initial or duplicate test. The final report is deemed negative. The risk of being positive is no greater whether the initial ELISA is positive as long as the repeat ELISA done is nonreactive or, in the case of 2 positive ELISA results, the Western blot is negative.

The Western blot is more specific because it looks at a number of antigens: a reactive test requires 2 of three antigen bands, including gp160 or 120, gp 41 and p24, while a negative test has no virus-specific bands.17 Intermediate tests result from the presence of one band. In low risk patients, such as pregnant women being screened, this usually signifies no infection. After six months, in many instances this test can revert to negative, but it frequently will not change. These persons should be considered negative if no risk factors are elicited. Those persons with risk factors, however, should be considered positive or at least watched closely for eventual seroconversion and counseled for risk reduction behavior.18

Other available tests, such as p24 antigen and PCR testing, can be used in certain situations, such as spouses/sex partners, newborns and other recent contacts, where timely medical intervention may actually prevent infection. The p24 antigen is now part of the screening armamentarium of blood banks, and can detect infection about one week before HIV antibodies can be measured.19 PCR testing can demonstrate significant viral loads within 10 days of infection.

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