Evaluation of an alternative HIV diagnostic algorithm using specimens from seroconversion panels and persons with established HIV infections

Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Hepatitis, STD, and TB Prevention, Atlanta, GA 30333, USA.
Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology (Impact Factor: 3.02). 12/2011; 52 Suppl 1(Suppl 1):S17-22. DOI: 10.1016/j.jcv.2011.09.011
Source: PubMed


The current algorithm for HIV diagnosis in the US involves screening with an immunoassay (IA) and supplemental testing with Western blot (WB) or immunofluorescence assay. Because of existence of more sensitive and specific FDA-approved assays that would also reduce the cost and turn-around time of testing compared to WB, several alternative algorithms have been evaluated. Recently, an alternative algorithm using a sensitive 3rd or 4th generation IA followed by an HIV-1 and HIV-2 discriminatory supplemental test on the initial IA-positive specimens was proposed. Concordant positive results indicate HIV-positive specimens and discordant results are resolved by nucleic acid amplification testing (NAAT).

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Available from: Silvina Masciotra, Jun 26, 2015
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    • "In practice, studies of these point-of-care tests showed that sampling of oral fluid identified fewer infections than plasma or whole blood and that point-of-care testing identified only 91% of antibody-positive men who have sex with men (MSM) and 80% of MSM detected by HIV RNA polymerase chain reaction.16,17 All antibody-based rapid assays are limited by a long window period, generally comparable to early-generation enzyme immunoassay tests and estimated to be up to 6–12 weeks.16,18–20 Data indicated that individuals were more likely to receive results from rapid tests as compared to standard assays, though it was unclear whether this led to more frequent linkage to care.21–24 "
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    ABSTRACT: Approximately 60% of human immunodeficiency virus (HIV)-infected individuals are unaware of their infection, and stigma and discrimination continue to threaten acceptance of HIV testing services worldwide. Self-testing for HIV has garnered controversy for years and the debate reignited with the approval of a point-of-care test for over-the-counter sale in the US in 2012. Here, we present arguments for and against HIV self-testing. The case in support of HIV self-testing contends that: the modality is highly acceptable, especially among the most at-risk individuals; self-testing empowers users, thus helping to normalize testing; and mutual partner testing has the potential to increase awareness of risk and avert condomless sex between discordant partners. Arguments against HIV self-testing include: cost limits access to those who need testing most; false-negative results, especially during the window period, may lead to false reassurance and could promote sex between discordant partners at the time of highest infectivity; opportunities for counseling, linkage to care, and diagnosis of other sexually transmitted infections may be missed; and self-testing leads to potential for coercion between partners. Research is needed to better define the risks of self-testing, especially as performance of the assays improves, and to delineate the benefits of programs designed to improve access to self-test kits, because this testing modality has numerous potential advantages and drawbacks.
    Full-text · Article · Aug 2014 · HIV/AIDS - Research and Palliative Care
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    • "Nonreactive 3rd generation IA results were obtained from three individuals with Abbott Combo RR, HIV-1 NAT reactive results. Our results are similar to those observed by others comparing the new HIV Diagnostic Algorithm or alternative algorithms to the conventional IA-WB algorithm [10] [11] [12] [13] [14] [15] [16] [17] [18]. Abbott Combo and MS HIV-1 concordantly reactive results were sufficient to identify 99.6% (918/922) of HIV-1 infected individuals. "
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    ABSTRACT: Objective: The Centers for Disease Control and Prevention and the Association of Public Health Laboratories have proposed a new HIV-1/2 Diagnostic Algorithm: a fourth-generation HIV-1/2 Ag/Ab immunoassay (IA) followed, when repeatedly reactive, by an HIV-1/HIV-2 antibody differentiation test, and if that is non-reactive, HIV-1 nucleic acid amplification testing (NAT). The objective of the study was to evaluate performance of the new algorithm after five months of utilization in our high volume, high HIV-1 seroprevalence public health population. Methods: Algorithm sensitivity and specificity was evaluated on 51,953 prospective serum or plasma specimens from individuals self-referring for HIV serostatus determination. Specimens were tested on the day of receipt or maintained at 4°C until the next testing opportunity. If the initial HIV-1/2 Ag/Ab IA (Abbott Combo) was nonreactive, a negative lab interpretation report would follow. If the initial IA was reactive, repeat screening in duplicate was immediately performed. Repeatedly reactive specimens were tested with an HIV-1/HIV-2 differentiation assay (Multispot [MS] HIV-1/HIV-2 Rapid Test) on the same or next workday. If the Abbott Combo-MS assays were discordant, HIV-1 NAT (APTIMA(®) HIV-1 RNA) was performed. In addition to the algorithm performance, we also evaluated the laboratory "specimen receipt to reporting" turnaround time (TAT). Results: The sensitivity and specificity of the new HIV Diagnostic Algorithm with serum and plasma specimens over the initial 5 month period was 100% (922/922) and 99.99% (51,030/51,031), respectively. Two algorithm-defined acute HIV-1 infections (AHI) were detected. In addition only 3 of the 992 MS secondary tests performed were interpreted as HIV-1 Indeterminate (HIV-1 recombinant gp41 reactivity only). Of these, 2 were HIV-1 NAT reactive, defined in-house as an early HIV infection (EHI) and one was HIV-1 NAT nonreactive, indicating a false positive initial screening result. Laboratory TAT for reporting concordant reactive Abbott Combo-MS results in ≤ 2 workdays was 96%, compared to 22% for reporting concordant reactive 3rd generation IA-Western blot results. Conclusions: In our public health testing population, results from the new HIV Diagnostic Algorithm exceeded those of the 3rd generation IA-WB algorithm with respect to HIV-1 sensitivity. The identification of two algorithm-defined AHIs provided the opportunity to inform these individuals of their HIV status and link them to medical care earlier than the scheduled posttest counseling appointment.
    Preview · Article · Dec 2013 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
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    • "In early stages of infection, from the acute period to the appearance of IgG, WB fails to confirm infection detected by nucleic acid amplification testing (NAAT) or p24 or containing only IgM antibodies. In early HIV-1 infections, reports indicate that NAAT is positive 26 days before the WB becomes positive and 4th generation IAs detect infection approximately 19 days before the WB becomes positive [2] [6]. It is important to detect acute HIV infections as soon as possible when viral loads are known to be high and likelihood of transmission is increased [9–14]. "
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    ABSTRACT: Until recently most testing algorithms in the United States (US) utilized Western blot (WB) as the supplemental test. CDC has proposed an algorithm for HIV diagnosis which includes an initial screen with a Combo Antigen/Antibody 4th generation-immunoassay (IA), followed by an HIV-1/2 discriminatory IA of initially reactive-IA specimens. Discordant results in the proposed algorithm are resolved by nucleic acid-amplification testing (NAAT). Evaluate the results obtained with the CDC proposed laboratory-based algorithm using specimens from men who have sex with men (MSM) obtained in five metropolitan statistical areas (MSAs). Specimens from 992 MSM from five MSAs participating in the CDC's National HIV Behavioral Surveillance System in 2011 were tested at local facilities and CDC. The five MSAs utilized algorithms of various screening assays and specimen types, and WB as the supplemental test. At the CDC, serum/plasma specimens were screened with 4th generation-IA and the Multispot HIV-1/HIV-2 discriminatory assay was used as the supplemental test. NAAT was used to resolve discordant results and to further identify acute HIV infections from all screened-non-reactive missed by the proposed algorithm. Performance of the proposed algorithm was compared to site-specific WB-based algorithms. The proposed algorithm detected 254 infections. The WB-based algorithms detected 19 fewer infections; 4 by oral fluid (OF) rapid testing and 15 by WB supplemental testing (12 OF and 3 blood). One acute infection was identified by NAAT from all screened-non-reactive specimens. The proposed algorithm identified more infections than the WB-based algorithms in a high-risk MSM population. OF testing was associated with most of the discordant results between algorithms. HIV testing with the proposed algorithm can increase diagnosis of infected individuals, including early infections.
    Full-text · Article · Dec 2013 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
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