Education programs also should address providers' confusion about HIV testing algorithms and interpretation of results. In low-prevalence areas, false positive results from initial screening with an ELISA (enzyme-linked immunosorbent assay) can account for at least two-thirds of all positive tests (if the prevalence of HIV in pregnant women is less than 5 per 10,000). By contrast, the rate of false positives in high-prevalence areas (200 per 10,000, for example) is about 5% (see Appendix K). Confirmatory testing with Western blot or immunofluorescence lowers false positives to almost zero. There are still problems with interpretation of indeterminate results, however, and providers need to know how to counsel women about the need for follow-up testing. Laboratories, under most circumstances, do not report initial positive results to patients until after confirmatory testing. Nevertheless, the committee was informed of several cases in which pregnant women were told of their positive initial ELISA test results, which turned out to be false positives, by providers who did not understand the need for confirmatory test results (Appendix G).
Education programs should also stress providers' potential malpractice liability for failing to offer an HIV test. As prenatal HIV testing increasingly becomes recognized as the standard of care, courts may rule that providers are negligent if they do not offer a test to a pregnant woman who later gives birth to an HIV-infected baby, or at least document the refusal of a test (King, 1991). As documented in Chapter 2, fear of malpractice has served as a powerful incentive for prenatal care providers to initiate other screening programs.
Information available to the committee through its workshops, site visits, and correspondence suggests a wide array of approaches to promote prenatal HIV testing by changing provider practices. Approaches include the preparation or dissemination of practice guidelines, such as those discussed in Chapter 6. There is also a variety of specific clinical policies that facilitate HIV testing, such as inclusion of HIV tests in the standard prenatal test panel and no longer requiring counseling as a prerequisite for HIV testing.
Clinical practice guidelines offer a means to facilitate HIV testing in the prenatal setting. Practice guidelines are "systematically developed statements to assist practitioners and patient decisions about appropriate health care for specific clinical circumstances" (IOM, 1990, 1992). Practice guidelines can be developed by federal or state health agencies, or by professional organizations, through a process of reviewing the relevant scientific and clinical literature and building consensus among pertinent professional and patient organizations. As described in Chapter 6, state and local health departments and a number of professional organizations have already prepared practice guidelines to implement the PHS counseling and testing guidelines (CDC, 1995b). Accepting this approach,