Guidance Statement 1: American College of Physicians (ACP) recommends that clinicians adopt routine screening for human immunodeficiency virus (HIV) and encourage patients to be tested.
The goal of screening for HIV is to identify patients with undiagnosed HIV so that timely treatment is provided and transmission is prevented. The ACP's guidance to perform routine screening of all patients is based on the following rationale and evidence. First, early identification and treatment for HIV provides substantial health benefit by extending the length of life of the person identified as having HIV. Modeling studies suggest that identification and successful treatment also probably reduce HIV transmission, both through changes in risk behavior and from suppression of viral load through treatment, although the magnitude of the risk reduction has not been assessed directly.
Second, risk-based screening has failed to identify a substantial proportion of people with HIV early in disease. Although risk-based screening has been recommended for more than 15 years, evidence from the Centers for Disease Control and Prevention (CDC) and Veterans Affairs indicate that almost half of patient are identified late in the course of disease, when they will no longer receive the maximum benefit from antiretroviral therapy. Thus, the effectiveness of risk-based screening has been limited because providers seldom actually perform risk assessments, and even if providers did such assessments in all patients, a substantial proportion of people with HIV would still be missed because they either are unaware that they are at increased risk or do not wish to disclose risk behaviors.
Third, routine opt-out screening (screening all individuals unless they decline to be tested) has been widely implemented and highly successful for prenatal HIV screening. Acceptance among women has been high, and mother-to-child transmission has been nearly eliminated in the United States. Whether specific informed consent for HIV testing is required varies by state, and clinicians should be aware of requirements in their practice setting.
Finally, strong evidence indicates that screening is cost-effective, even when the prevalence of HIV is low.
The ACP encourages clinicians to counsel patients to reduce risky behaviors when such counseling is feasible.
The Clinical Efficacy Assessment Subcommittee (CEAS) recognizes that further evidence on several aspects of routine screening would be useful. These include the degree to which patients will participate in screening, the effectiveness of routine screening in reducing risky behaviors in low-risk settings, and the prevalence of undiagnosed HIV infection in diverse patient populations. Nonetheless, risk-based screening has failed to identify a substantial proportion of people with HIV and, even if implemented universally, would still miss a substantial proportion of people with HIV. The CEAS judged that the benefits of routine screening outweighed the harms and that routine screening is therefore warranted. Several aspects of screening deserve particular emphasis.
The CEAS notes the importance of screening patients who are at increased risk for HIV infection. Many, perhaps most, patients at high risk have not been tested, so efforts to reach these patients are especially important. Groups at increased risk include men who have sex with men; men and women who have unprotected sex with multiple partners; past or current injection drug users; men and women who exchange sex for money or drugs or have sexual partners who do; individuals whose past or current sexual partners were infected with HIV, were bisexual, or were injection drug users; persons being treated for sexually transmitted diseases (STDs); and persons with a history of blood transfusion between 1978 and 1985. Patients who receive health care in high-prevalence or high-risk health care settings are also a high priority for screening. High-risk settings include STD clinics, correctional facilities, homeless shelters, tuberculosis clinics, clinics serving men who have sex with men, substance abuse clinics, and adolescent health clinics with a high prevalence of STDs. High-risk patients who are tested because of a viral syndrome that may represent acute HIV infection may require additional testing in addition to HIV antibody tests, because anti-HIV antibody tests may not be reactive during acute infection.
The CEAS also notes the importance of screening women who are pregnant. The United States Preventative Services Task Force (USPSTF), Centers for Disease Control and Prevention (CDC), and American College of Obstetricians and Gynecologists guidelines recommend HIV screening during pregnancy. Screening should be performed during each pregnancy.
The CDC recommends that patients age 13 to 64 years be screened for HIV. Less evidence is available on screening older patients, but nationally, approximately 20% of patients with HIV are older than 50 years.
Prevalence of HIV
The CDC recommends routine screening unless the prevalence of HIV in a population is less than 0.1%. This threshold is reasonable given the evidence from cost-effectiveness analyses. The CEAS recognizes that the prevalence of HIV is not known in most populations. A practical approach to routine screening is to begin screening and if no patients with undiagnosed disease are found after a substantial number of patients have been tested, then the need for screening should be reassessed. If no HIV-infected patients are found after screening approximately 4000 patients, the 95% confidence interval (CI) for prevalence will be less than 0.1%.
Education About Risk Factors
Clinicians should discuss the risk factors of HIV infection with their patients. Adolescents and older patients in particular may be unaware of behaviors that may put them at increased risk for HIV.
Rapid Versus Traditional Testing
Traditional testing (enzyme immunoassay followed by Western blot) has very high sensitivity and specificity, so false-positive results are rare. However, results from traditional testing are not rapidly available. Rapid tests provide results within 1 hour, an important advantage that increases the number of patients who receive their result. However, a recently published study found relatively high false-positive rates with an oral rapid test; other reports have noted increased false-positive rates with oral rapid tests. Patients and clinicians should be aware that any positive rapid test result must be confirmed with traditional testing.
Guidance Statement 2: ACP recommends that clinicians determine the need for repeat screening on an individual basis.
The importance of repeated HIV screening depends on whether patients have ongoing risk for HIV infection. Higher-risk patients should be retested more frequently than lower-risk patients. The USPSTF does not make recommendations about the frequency of screening. The CDC guideline recommends that providers screen patients at high risk for HIV at least annually. The CDC defines persons likely to be at high risk as injection drug users and their sexual partners, persons who exchange sex for money or drugs, sexual partners of HIV-infected persons, men who have sex with men, and heterosexual persons who have had or whose sexual partners have had more than 1 sexual partner since their most recent HIV test.
Apart from high-risk groups, the decision to retest persons should be based on clinical judgment.