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JULY/AUGUST 2008
Main Article:
Rapid HIV Testing: Coming to a jail near you?
Brooke E. Hoots, MSPH The University of North Carolina School of Public Health David A. Wohl, MD Associate Professor of Medicine University of North Carolina AIDS Clinical Research Unit Introduction An estimated 1.2 million people in the United States are living with HIV/AIDS,1 and an estimated 25% of these people are unaware of their HIV infection.2 In response, the Centers for Disease Control and Prevention (CDC) in September 2006 issued their Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings, aiming to reduce barriers to HIV testing and increase the number of Americans who know their HIV status.3 A centerpiece of these recommendations is a move to opt-out HIV screening for all patients ages 13-64 years in all health care settings, including correctional health care facilities. The basis for this recommendation is that by increasing the availability of HIV testing the number of people who know their result will also increase and, as demonstrated, will subsequently reduce behaviors likely to transmit HIV, and will help reduce the spread of the virus. 4,5 Although detection of HIV infection is a cornerstone of HIV prevention, testing alone is insufficient. According to the CDC, almost one-third of individuals in 2000 who tested and found to be HIV-infected did not return to receive their test result.6 The turn-around time for conventional HIV testing has often been an insurmountable obstacle to HIV screening of at-risk populations such as those who are homeless or migratory. A failure to return for HIV test results is not unique to community HIV screening; the transient nature of those who are jailed has prevented wider spread HIV testing in this setting. A study of the HIV testing experiences of jail inmates conducted in Rhode Island found that 50% of those who had previously been tested for the virus had not received the result of the test even though a majority of prior HIV screening had been performed in correctional settings.7 Since becoming available in the United States in 2002, rapid HIV tests have allowed for the expansion of HIV screening in both medical and non-medical settings, including prisons and jails.8 Rapid HIV tests yield results in less than 30 minutes and substantially increase the number of people who receive their test result by eliminating the need for a return visit, and are becoming increasingly utilized in non-clinical settings such as community-based screening events.9 Rapid HIV testing is particularly suited to use in jails due to the transient nature of inmates in this environment. Testing can be conducted quickly, does not require extensive training of the tester, and the results are provided immediately. Another Rhode Island study found that among 95 jail inmates, 79% of whom had not received an HIV test result during a prior incarceration, 100% were informed of the results of their rapid HIV test during their current jail stay.10 FDA-approved rapid tests Since February 2002, six rapid tests have been approved by the Food and Drug Administration (FDA) (See HIV 101).11 Four of these tests (OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, Clearview HIV-1/2 STAT-PAK, Clearview COMPLETE HIV 1/2, and Uni-Gold Recombigen HIV Test) are approved for use with whole blood specimens obtained by finger stick or venipuncture. OraQuick ADVANCE may also be used with oral fluid samples. These tests have received waivers under the Clinical Laboratory Improvement Amendments (CLIA) that set quality standards for all testing on human specimens, enabling these tests to be used in settings that do not include laboratories when they utilize whole blood specimens or oral fluid.12, 13 Settings using CLIA-waived tests only need to enroll in CLIA, pay a fee, and follow the test manufacturer's instructions for use. The two tests that only use serum or plasma samples (MultiSpot HIV-1/HIV-2 Rapid Test and Reveal G3 Rapid HIV-1 Antibody Test) are classified as "moderately complex" under CLIA and are not waived, meaning they are subject to specific laboratory and personnel requirements. Similarly, when the four tests with waivers for use with oral fluid and/or whole blood specimens are used with plasma or serum samples (only plasma in the case of OraQuick ADVANCE), they are no longer CLIA-waived. All of the FDA-approved rapid tests are interpreted visually. The test strip or membrane is covered with HIV antigens that bind HIV antibodies that may be present in the patient specimen. The test kits also contain colorimetric reagents that generally bind to a control region on the test strip and to HIV antibodies to create an indicator that is visually detectable.14 With the exception of the MultiSpot HIV-1/HIV-2 Rapid Test, which takes about 10-15 minutes to conduct, all of the rapid tests take less than 5 minutes to set up and perform.12 The window periods for reading the results as measured from the last step of the testing process are listed in Table 1. If the tests are not read within these window periods, they are considered invalid. It is therefore important to make sure that personnel coordinate patient intake and processing to fit within these window periods. Sensitivity and specificity All of the FDA-approved rapid tests have sensitivities and specificities that are comparable to conventional blood-based HIV enzyme immunoassays (EIAs) antibody tests.15 Sensitivity is the probability that the test result will be positive given that the person is truly HIV-infected, while specificity is the probability that the test result will be negative given that the person is truly HIV-uninfected. While the sensitivity and specificity of a test are constant properties, the predictive value, or the usefulness of the test in classifying people with infection, varies depending on the prevalence of disease in the population being tested.16 The negative predictive value of a rapid HIV test, or the probability that a person is HIV-uninfected given that his or her test is negative, is high at the HIV prevalence observed in most testing sites in the US.17 However, the positive predictive value of a rapid test, or the probability that a person is HIV-infected given that his or her test is reactive, is lower in populations with low HIV prevalence (For more information on why this is true, visit: http://www.cdc.gov/hiv/topics/testing/rapid/index.html. Therefore, in correctional settings where the prevalence of HIV infection is generally higher than the general population, the positive predictive value of rapid HIV testing will likely exceed that of most community settings. Reactive rapid tests results, like conventional EIAs, are considered preliminary and require confirmatory testing to rule out false-positive results.16 Confirmatory testing is usually done with a Western blot or indirect immunoflourescence assay.15 Recently, several clusters of higher than expected numbers of false-positive results have been noted in settings using rapid HIV tests of oral fluid.18 As reported in the Morbidity and Mortality Weekly Report (MMWR), the causes of these clusters have not been elucidated, but investigations are under way to determine what factors might be associated with this unexplained variability. Several programs using oral fluid-based testing have changed their procedures and now repeat the rapid test on whole-blood specimens from patients who have reactive oral fluid tests. This strategy allows the programs to take advantage of the convenience of oral fluid rapid testing while decreasing the number of preliminary false-positives. Regardless of the test used, it is important to remember that confirmatory testing is required to confirm all reactive rapid HIV tests. Communicating the meaning of the rapid test result Because the negative predictive value of a rapid HIV test is high, a person who receives a negative HIV rapid test result can be told that he or she is not HIV-infected.14 However, if a person has had a possible recent exposure to HIV (within 3 months), he or she could be in the acute phase of HIV infection and have not yet developed detectable HIV antibodies. Such persons should be counseled regarding the possibility of acute HIV infection and be retested within 3 months. If symptoms or high suspicion for acute HIV infection are present, testing for HIV RNA may be warranted. Individuals with reactive rapid test results should be counseled on risk-reduction behaviors while awaiting the results of confirmatory testing. The CDC recommend conveying to the patient that the preliminary test is positive and that the individual should take precautions to avoid transmitting the virus to others while awaiting confirmatory testing.19 If the confirmatory test result is negative or indeterminate, the individual should be retested after one month to rule out test error and the possibility of early HIV infection that may not yet be detectable by Western blot.20 An indeterminate test may be an indication of early HIV infection and testing for acute HIV with an HIV RNA test may be necessary. Consultation with an HIV expert should be sought in such cases. HIV counseling with rapid testing The FDA requires that individuals who undergo rapid testing receive an information sheet provided by each manufacturer with its rapid HIV test kits.14 This sheet includes general information on HIV and AIDS as well as specifics about the test and what the results mean and don’t mean. Clients should also receive prevention counseling. With conventional HIV testing, there are two visit opportunities for prevention counseling for clients who return for their results. With rapid testing, there may be either one or two opportunities for counseling depending on whether or not confirmatory testing is required and the patient returns for these test results.19 Point-of-care testing requires that personnel have the ability and the privacy to provide positive test results on the spot. If an individual with a reactive rapid test does not return for confirmatory testing results, he or she should at least leave the initial visit knowing that there is a high probability of infection.14 Rapid HIV testing in jails While rapid HIV testing has been incorporated into the HIV screening procedures of jails across the United States, there are few published reports describing their application in this setting. Results of a CDC-supported effort to introduce rapid HIV testing for screening of jail inmates in Florida, Louisiana, New York, and Wisconsin provide some of the best data on this approach.8 Between 2003 and 2006, 33,211 inmates, 6% of all those booked, were voluntarily HIV tested with a rapid test between. More than 99% of these inmates received their HIV test results; 1.3% had a reactive test result and 97% of those who underwent confirmatory testing were found to be HIV-infected. For two-thirds of those found to be HIV-infected, the diagnosis was new. In these settings, rapid HIV testing was found to be feasible and did lead to the identification of over 250 individuals who were unaware of their HIV infection. An analysis of the costs associated with this CDC demonstration project, including the cost of identifying previously undiagnosed HIV infection, has also been published.21 This analysis focused on data collected from 2004 to 2005. Although the costs were extremely variable by site, the study found that the average cost of HIV testing for those without infection was between $29.46 and $44.98. The cost of testing was significantly higher for HIV-infected inmates and was estimated between $71.37 and $137.72 per inmate. The discrepancy in costs relative to HIV serostatus is due to the extra post-test counseling required for individuals who test positive for HIV. Most of the cost of rapid HIV testing was due to variable costs, including time for counseling and testing, nondurable goods and supplies, and test kits. Overall, the average cost per newly diagnosed HIV infection ranged from a low of $2,451 to high of $25,288. The high end of the spectrum of the cost per new HIV diagnosis is a function of greater travel and other expenses at one site coupled with a low overall HIV prevalence in that state. Conclusions Rapid testing should be used to encourage behavior change to limit the spread of HIV infection and to link those who test positive into a system of care. Such testing reduces significant barriers to individuals learning their HIV status, allows for HIV testing opportunities in settings without committed laboratories, and facilitates patients receiving their test results at the testing visit. HIV screening of jailed inmates with rapid HIV tests is attractive given the quick turn around time for results and the accuracy of these tests. However, such testing is not without costs, including the expense of the tests themselves, the training of staff to perform the testing, and counseling and confirmatory testing, when necessary. The cost per new HIV diagnosis drops with increasing prevalence of HIV infection. Therefore, jails in areas with a higher prevalence of HIV infection may find rapid HIV testing to be more affordable than those where HIV infection is less common. In all settings, the benefits of the detection of undiagnosed HIV infection, including prevention of opportunistic conditions and secondary transmission of the virus, may well justify any added expense. References: 1. Glynn M, Rhodes P. Estimated HIV prevalence in the United States at the end of 2003. National HIV Prevention Conference; June 2005; Atlanta. Abstract T1-B1101. 2. CDC. Number of persons tested for HIV United States, 2002. MMWR 2004;53:1110-3. CDC. Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings. MMWR 2006;55(RR14):1-17. 4. Roberts KJ, Grusky O, Swanson AN. Outcomes of Blood and Oral Fluid Rapid HIV Testing: A Literature Review, 2000-2006. AIDS Patient Care STDs 2007;21(9):621-637. 5. Marks G, Crepaz N, Senterfitt W, Janssen RS. Meta-analysis of high-risk sexual behavior in persons aware and unaware they are infected with HIV in the United States: implications for HIV prevention programs. J Acquir Immune Defic Syndr 2005;39:44-53. 6. CDC. Advancing HIV prevention: new strategies for a changing epidemic--United States 2003. MMWR 2003;52:329-32. 7. Beckwith C, Cohen J, Shannon C, Raz L, Rich JD, Lally MA. HIV testing experiences among male and female inmates in Rhode Island. AIDS Read 2007;17(9):459-64. 8. MacGowan R, Margolis A, Richardson-Moore A, et al. Voluntary Rapid Human Immunodeficiency Virus (HIV) Testing in Jails. Sex Transm Dis 2007;34(11):000-000. 9. Hutchinson AB, Branson BM, Kim A, Farmham PG. A meta-analysis of the effectiveness of alternative HIV counseling and testing methods to increase knowledge of HIV status. AIDS 2006;20:1597-1604. 10. Beckwith CG, Atunah-Jay S, Cohen J, et al. Feasibility and acceptability of rapid HIV testing in jail. AIDS Patient Care STDS 2007;21(1):41-47. 11. CDC. FDA-Approved Rapid HIV Antibody Screening Tests. Atlanta, GA: US Department of Health and Human Services, CDC, 2008. Available at: http://www.cdc.gov/hiv/topics/testing/rapid/rt-comparison.htm. Accessed 11 June 2008. 12. CDC. FDA-Approved Rapid HIV Antibody Screening Tests – Purchasing Details. Atlanta, GA: US Department of Health and Human Services, CDC, 2008. Available at: http://www.cdc.gov/hiv/topics/testing/rapid/rt-purchasing.htm. Accessed 11 June 2008. 13. FDA. Ora-Quick ADVANCE Rapid HIV-1/2 Antibody Test. Rockville, MD: US Department of Health and Human Services, FDA, 2004. Available at: http://www.fda.gov/cdrh/oivd/CLIA-oraquick.html. Accessed 11 June 2008. 14. Greenwald JL, Burstein GR, Pincus J, Branson B. A Rapid Review of Rapid HIV Antibody Tests. Curr Infect Dis Rep 2006;8:125-31. 15. Branson BM. State of the Art for Diagnosis of HIV Infection. CID 2007;45:S221-5. 16. Rothman, Kenneth J. Epidemiology: An Introduction. New York: Oxford UP, 2002. 17. CDC. Update: HIV Counseling and Testing Using Rapid Tests – United States 1995. MMWR 1998;47(11):211-15. 18. CDC. False-Positive Oral Fluid Rapid HIV Tests--New York City, 2005-2008. MMWR 2008;57:1-5. 19. CDC. HIV Counseling with Rapid Tests. Atlanta, GA: US Department of Health and Human Services, CDC, 2007. Available at: http://www.cdc.gov/hiv/topics/testing/resources/factsheets/rt_counseling.htm. Accessed 11 June 2008. 20. CDC. Protocols for confirmation of reactive rapid HIV tests. MMWR 2004;53:221-2. 21. Shrestha RK, Sansom SL, Richardson-Moore A, et al. Costs of Voluntary Rapid HIV Testing and Counseling in Jails in 4 States-Advancing HIV Prevention Demonstration Project, 2003-2006. Sex Transm Dis 2007;34(11):000-000. |
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