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100%. 98%. 98%. 96%. 96%. 94%. 93%. 94%. 93%. 92%. 92%. 91%. 92%. 90%. Se. 88%. 86%. 86%. 84%. 82%. 80%. 78%. 1st Gen EIA. Multi-Spot HIV 1/2. Clearview Stat-Pak. Unigold Recombigen. Oraquick Advance (Blood). Oraquick Advance (Oral Fluid). Genetic Systems HIV 1/2 Plus 0.
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1st Gen EIA
Multi-Spot HIV 1/2
Oraquick Advance (Blood)
Oraquick Advance (Oral Fluid)
Genetic Systems HIV 1/2 Plus 0
ARCHITECT HIV Ag/Ab Combo
Determine HIV-1/2 Ag/Ab Combo
A Clinical Study of Antigen-Antibody Rapid Testing for Acute HIV InfectionChristopher D. Pilcher1, Brian Louie2, Sheila Keating3, Mark Pandori2, Falk Fish4, Tomer Keren4, Sally Liska2, Michael P. Busch3, Frederick M. Hecht1, Jeffrey Klausner1,2 and Grant Colfax1,2from 1UCSF HIV/AIDS Division; 2SF Department of Public Health; 3Blood Systems Research Institute; 4Inverness Medical Innovations
Acute HIV infections, as a proportion of all HIV cases detected
by each testing program.
The % of all HIV infected cases
A key factor influencing HIV test performance, particularly in higher-risk testing sites, is the ability to detect acute HIV cases. These cases are often negative on tests designed to detect only anti-HIV IgG
“4th generation” immunoassays (e.g., the ARCHITECT HIV Ag/Ab Combo) can detect both HIV p24 antigen and anti-HIV antibodies for earlier detection. A new rapid test (the Determine HIV-1/2 Ag/Ab Combo) is also designed to detect HIV p24 antigen and anti-HIV antibodies.
We sought to measure the potential impact of these new screening tests on the performance of real-world, public health and research testing programs in San Francisco.
Methods - Testing
Antibody (Ab)-plus-RNA testing reference standard: The complete
algorithm, including Ab and RNA tests, was used to define HIV infection.
The combined reference standard was used to determine
Sensitivity, Specificity and Positive/Negative Predictive Values for each
screening assay. Western blot was used to categorize samples as
representing acute (WB negative/indeterminate) or established (WB
positive) HIV infection.
identified that were Western blot
negative or indeterminate is shown.
The majority of RNA + patients found in high risk testing populations (high risk MSM, non-targeted STD clinic VCT, partner services and nPEP) were detectable by the 4th generation EIA or by the new rapid Ag/Ab combo assay, but not by 1st generation or even 3rd generation EIAs.
1st Gen EIA
Programs with the highest yield of acute HIV infections were those targeting patients with high risk exposures
Genetic Systems HIV
% Acute Infections Positive on Each Test
ARCHITECT HIV Ag/
High Risk MSM
High Risk MSM
Acute HIV Diagnostic
Sensitivity was compared head-to-head in the high risk MSM testing population, The sensitivity estimates associated with each rapid test (light blue) and central lab immunoassay (dark blue) are shown.
Despite differences in clinical sensitivity, negative predictive values for each test to were >99.5%.
Specificity was estimated to be 100.00% for all immunoassays.
Oraquick Advance specificity was lower on oral fluid (Sp 99.86) vs. blood (99.96).
The Determine HIV Ag/Ab Combo correctly identified 80 of 81 HIV negative Options specimens, with 1 false positive result (Sp 98.9).
) RNA (+)
) RNA (
Rapid Test Panel
Methods - Specimens
Testing programs were included that used both HIV antibody and HIV RNA
amplification tests in their diagnostic algorithm:
High Risk MSM, Targeted Testing Population (n=6661)— MSM at public
testing sites meeting high risk criteria (sex with HIV+, unprotected anal
intercourse, or STD)
STD Clinic Population (n=14573)— attendees to the muncipal STD clinic,
not meeting above criteria
Non-occupational Post Exposure Prophylaxis (nPEP) Population
(n=989)— patients evaluated for, or receiving, nPEP
Partner Services (PS) Testing Population (n=173)— sexual or
needlesharing partners to newly diagnosed HIV+
Acute HIV Diagnostic Testing Population (n=1114; 1998-2008)— patients
screened for having acute HIV by the UCSF Options study based on acute
retroviral symptoms and/or high risk exposure.
Central Lab Test Panel
Gen EIA (
Gen IA (Abbott ARCHITECT HIV Ag/
Western Blot (
Head to head comparative performance evaluation: Acute specimens (RNA+, WB- or indeterminate) were submitted to Rapid Test and Central Lab panel tests. Sensitivity and Negative Predictive Values (NPV) were calculated for each panel test, assuming 100% detection of WB positive specimens.
Determine HIV-1/2 Ag/Ab Combo: Rapid Test Readout
The work was supported by R01- MH068686; we are grateful to Shelley Facente for analysis and to John Hackett, Jr. for providing 4th generation IA data, previously submitted for publication (Pandori MW, Hackett Jr., Louie B, et al., as “Assessment of the Ability of a Fourth Generation Immunoassay for HIV Antibody and p24 Antigen to Detect both Acute and Recent HIV Infection in a High-Risk Setting.”)