Supplementary Online Content Peters PJ, Westheimer E, Cohen S, et al. Screening yield of HIV antigen/antibody combination and pooled HIV RNA testing for acute HIV infection in a high-prevalence population. JAMA. doi:10.1001/jama.2016.0286. eappendix 1. Methods eappendix 2. Results etable 1. Acute HIV Infection Detection by Assay The STOP Study, September 2011-October 2013 etable 2. HIV Testing Results for Patients With False-Negative Pooled HIV RNA Test Results The STOP Study, September 2011-October 2013 efigure. Sequence of Appearance of Laboratory Markers for HIV-1 Infection ereferences This supplementary material has been provided by the authors to give readers additional information about their work.
eappendix 1. Methods The advantages of Multispot as a confirmatory test include that (1) it can differentiate HIV-1 and HIV-2 antibodies, (2) it has fewer indeterminate results, (3) it can be performed in all clinical labs, and (4) it is rapid. In the primary analysis, acute HIV infection required only a negative rapid HIV test result to demonstrate the absence of HIV antibody as this approach is consistent with how health departments and testing sites approach acute infection. In a supplemental analysis (see supplemental results), a serological definition of acute HIV infection was used that required both a negative rapid test and a negative or indeterminate Multispot test result 1. As false negative results can occur with rapid HIV tests, this more stringent serological definition of acute HIV infection was used to quantify how many false negative rapid HIV tests may have occurred.
eappendix 2. Results All acute infections detected by HIV Ag/Ab combination testing were also tested with the Multispot antibody assay. Among these 134 acute infections, 97 (72%) specimens were negative on Multispot confirmatory testing (anti-hiv-1 IgG antibody was not detected), 10 (7%) specimens were HIV-1 indeterminate, and 27 (20%) specimens were reactive (anti-hiv-1 IgG antibody was detected). Among these 27 Multispot reactive results, 17 specimens were consistent with early or acute infection based on other test results, including the following (not mutually exclusive): a documented negative HIV test result in the previous 6 months (n=11), an HIV-1 viral load >500,000 copies/ml (n=10), or a negative Western blot / IFA result (n=2). For the remaining 10 Multispot reactive results, a false-negative rapid test result in individuals with established HIV infection could not be ruled out. Among the 93 false-positive Ag/Ab combination test results, Multispot testing on two specimens was HIV-1 indeterminate, two specimens were HIV-2 reactive (but negative on further HIV-2 testing), and the remaining 89 specimens were negative.
etable 1. Acute HIV Infection Detection by Assay The STOP Study, September 2011 October 2013 HIV Ag/Ab Combination Assay Pooled HIV-1 RNA Testing Detectable 130 (77.4%) 4 (2.4%) Nonreactive 34 (20.2%) 0 (0%) Ag/Ab = Antigen/Antibody
etable 2. HIV testing results for patients with false negative pooled HIV RNA test results The STOP Study, September 2011 October 2013 Patient RNA1 HIV Ag/Ab Combination Assay S/CO = 2.43 Pooled HIV RNA Testing (pool= 10) Viral load (copies/ml) Other Antibody Results 45 Rapid HIV test negative Multispot HIV-1 reactive WB positive IFA positive Comments Evidence of elite HIV-1 control without antiretrovirals* RNA2 S/CO = 5.36 (pool= 10) 59 Rapid HIV test negative Multispot HIV-1 reactive IFA positive WB positive Evidence of elite HIV-1 control without antiretrovirals* RNA3 S/CO = 13.44 (pool= 16) <400 Rapid HIV test negative Multispot HIV-1 reactive WB positive Individual qualitative HIV-1 RNA detected RNA4 S/CO = 1.26 (pool= 80) 120,310 Rapid HIV test negative Multispot nonreactive WB negative Likely RNA testing lab error Ag/Ab = Antigen/Antibody; S/CO = signal-to-cut-off ratio; WB = Western blot; IFA = HIV-1 immunofluorescent assay *A small proportion (< 0.1%) of HIV-infected persons have undetectable HIV viremia (HIV RNA <50 copies/ml) without antiretrovirals and these patients have been classified as elite controllers. Conventional HIV RNA assays (including pooled HIV RNA testing) can be undetectable in these patients and ultrasensitive HIV RNA assays are often required to confirm HIV infection.
efigure. Sequence of appearance of laboratory markers for HIV-1 infection HIV RNA (plasma) HIV Antibody HIV p24 Antigen Infection Days 0 10 20 30 40 50 60 70 80 90 100 Detection of HIV RNA HIV p24 Antigen* HIV IgG Antibody by rapid HIV test and Western blot Phase of Infection Acute HIV Infection Established HIV Infection * Detectable by lab-based HIV Ag/Ab combination immunoassays Note. Units for vertical axis are not noted because their magnitude differs for RNA, p24 antigen, and antibody
ereferences. 1. Centers for Disease Control and Prevention and Association of Public Health Laboratories. Laboratory Testing for the Diagnosis of HIV Infection: Updated Recommendations. Available at http://stacks.cdc.gov/view/cdc/23447. Published June 27, 2014. Accessed July 3, 2014.