4th Generation HIV Research Articles

Validation and Comparison Study for Fourth Generation HIV Test Kit

Abstract Introduction/Objective CDC recommends the use of 4th generation HIV test as the first line of screening. Alere Determine HIV – 1/2 Ag/Ab Combo (Abbott Diagnostics Scarborough, Inc., Scarborough, Maine) (Alere) is a qualitative 4thgeneration assay that detects HIV 1/2 antibodies and p24 antigen. In this validation study, Alere was compared with OraQuick Advance Rapid HIV 1/2 Antibody test (OraSure Technologies, Inc., Bethlehem, PA) (Oraquick), a qualitative 3rd generation test and BioPlex (Bio-Rad Laboratories, Hercules, California) a 5th generation test that detects and differentiates between HIV 1 and 2 antibodies and p24 antigen. Methods/Case Report Comparison study: Forty-five samples were tested simultaneously on the three assays. Results for the patient samples were confirmed with Geenius (Bio- Rad Marnes-La-Coquette, France) or PCR assays for antibody or antigen positive cases respectively. Precision study A HIV-1 antibody positive and an all-negative sample were tested 10 times each to validate the precision of the Alere test. Dilution study A positive sample for HIV-1 antibody was used for dilution with a HIV negative serum sample. Diluted samples from 1:10 to 1:1000 were tested using Alere and BioPlex. Results (if a Case Study enter NA) Comparison study revealed that sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for Alere test were 100%. Sensitivity for Oraquick was 86.6% and NPV was 77.77%. Specificity and PPV were 100%. BioPlex showed sensitivity and NPV of 100%, but specificity was 78.5% and PPV was 90.90%. Precision study showed reproducible results on the Alere test. Dilution study revealed that Alere assay gave positive results up to 1:300 dilution, and BioPlex assay was positive up to 1:500 dilution. Conclusion Our studies showed that Alere had the sensitivity and specificity of 100% making it an effective screening test in acute settings. BioPlex assay demonstrated that it was the most sensitive test with quantitative index for the HIV 1 and 2 antibodies and p24 antigen. Therefore, both Alere and BioPlex tests are good initial screening tests

Sensitivity and specificity of OraQuick® HIV self-test compared to a 4th generation laboratory reference standard algorithm in urban and rural Zambia

BackgroundHIV self-testing (HIVST) has the potential to increase coverage of HIV testing, but concerns exist about intended users’ ability to correctly perform and interpret tests, especially in poor communities with low literacy rates. We assessed the clinical performance of the 2016 prototype OraQuick® HIV Self-Test in rural and urban communities in Zambia to assess the sensitivity and specificity of the test compared to the national HIV rapid diagnostic test (RDT) algorithm and a laboratory reference standard using 4th generation enzyme immunoassays and HIV RNA detection.MethodsParticipants were recruited from randomly selected rural and urban households and one urban health facility between May 2016 and June 2017. Participants received a brief demonstration of the self-test, and then self-tested without further assistance. The research team re-read the self-test, repeated the self-test, drew blood for the laboratory reference, and conducted RDTs following the national HIV testing algorithm (Determine™ HIV1/2 (Alere) confirmed using Unigold™ HIV1/2 (Trinity Biotech)). Selected participants (N = 85) were videotaped whilst conducting the testing to observe common errors.ResultsInitial piloting showed that written instructions alone were inadequate, and a demonstration of self-test use was required. Of 2,566 self-test users, 2,557 (99.6%) were able to interpret their result. Of participants who were videoed 75/84 (89.3%) completed all steps of the procedure correctly.Agreement between the user-read result and the researcher-read result was 99.1%. Compared to the RDT algorithm, user-conducted HIVST was 94.1% sensitive (95%CI: 90.2–96.7) and 99.7% specific (95%CI: 99.3–99.9). Compared to the laboratory reference, both user-conducted HIVST (sensitivity 87.5%, 95%CI: 82.70–91.3; specificity 99.7%, 95%CI: 99.4–99.9) and the national RDT algorithm (sensitivity 93.4%, 95%CI: 89.7–96.1%; specificity 100% (95%CI: 99.8–100%) had considerably lower sensitivity.ConclusionsSelf-testers in Zambia who used OraQuick® HIV Self-Test achieved reasonable clinical performance compared to the national RDT algorithm. However, sensitivity of the self-test was reduced compared to a laboratory reference standard, as was the national RDT algorithm. In-person demonstration, along with the written manufacturer instructions, was needed to obtain accurate results. Programmes introducing self-care diagnostics should pilot and optimise support materials to ensure they are appropriately adapted to context.

Performance evaluation and optimized reporting workflow for HIV diagnostic screening and confirmatory tests in a low prevalence setting.

Our institution utilizes an antigen/antibody screening test followed by a confirmatory antibody assay for preliminary positive results. Given the low prevalence for HIV infections in our institution's county, we suspect that a substantial portion of the reactive screens are false positives. We aimed to characterize the false positivity rate of the HIV screening test performed at Stanford Health Care. In parallel, we modified our reporting workflow to release both the screening and confirmatory results simultaneously to mitigate the stress of a presumptive positive test. We reviewed 45,296 eligible HIV screen specimens that underwent the Abbott ARCHITECT™ 4th generation HIV antigen/antibody combination assay between August 5, 2016 and March 16, 2021. Final sample signal/cutoff (S/CO) ratios ≥ 1 were deemed positive, which triggers a reflex order for the confirmatory Bio-Rad Geenius™ HIV 1/2 Supplemental Assay. Additional chart review was performed for positive screen cases with negative or indeterminate confirmatory results. Our institution demonstrated a 0.28% (128/45,296) positive screen rate, with 12.5% (16/128) of these samples confirmed as false positives based on a negative HIV-1 RNA test. Median S/CO ratios of true positive screens were significantly higher than those with negative or indeterminate confirmatory tests (602.27vs 2.98; p=0.0000323). We implemented a new synchronized reporting system for positive screens, which co-releases screen and confirmatory reports without compromise in the overall turnaround time. Our study demonstrates a relatively high percentage of false positive screens. Subsequently, by providing a more complete picture up front, our new reporting pipeline may reduce anxiety of a stand-alone positive screen and optimize downstream clinical decision-making.

4th Generation HIV screening in the emergency department: net profit or loss for hospitals?

ABSTRACT The objective of this study was to determine hospital costs and revenue of universal opt-out HIV ED screening. An electronic medical record (EMR)-directed, automated ED screening program was instituted at an academic medical center in San Diego, California. A base model calculated net income in US dollars for the hospital by comparing annual testing costs with reimbursements using payor mixes and cost variables. To account for differences in payor mixes, testing costs, and reimbursement rates across hospitals in the US, we performed a probabilistic sensitivity analysis. The base model included a total of 12,513 annual 4th generation HIV tests with the following payor mix: 18% Medicare, 9% MediCal, 28% commercial and 8% self-payers, with the remainder being capitated contracts. The base model resulted in a net profit for the hospital. In the probabilistic sensitivity analysis, universal 4th generation HIV screening resulted in a net profit for the hospital in 81.9% of simulations. Universal 4th generation opt-out HIV screening in EDs resulted in a net profit to an academic hospital. Sensitivity analysis indicated that ED HIV screening results in a net-profit for the majority of simulations, with higher proportions of self-payers being the major predictor of a net loss.

Acute human immunodeficiency testing and linkage to Care: An evaluation of community-based 4th generation antigen/antibody testing

As a relatively novel testing algorithm, the experience with 4th generation HIV testing and linkage to care outcomes is limited. The purpose of this study is to report descriptive outcomes regarding patients with acute HIV infection who received antigen/antibody (Ag/Ab) reactive results and linkage to care services. HIV testing and linkage data from four AIDS Healthcare Foundation (AHF) Wellness Centers in Los Angeles County, CA were retrospectively reviewed from January 15, 2016 to May 26, 2018. Patients were screened using the INSTI® HIV-1/HIV-2 Rapid Antibody Test (bioLytical, Richmond, BC). A negative result reflexed to an HIV test on the Abbott Architect Ag/Ab Assay (Abbott Laboratories, Lake Bluff, IL). Out of the total 11,173 patient specimens processed on the Architect platform, 56 received preliminary reactive results and 42 returned for confirmatory viral load testing. Twenty-seven (64%) of the 42 patients were confirmed to be acutely infected with HIV. All 27 patients acutely infected with HIV were linked into care: 22 were linked into AHF’s primary care and the remaining five sought care with a primary care provider external to AHF. Despite low positivity, the 27 acutely HIV-infected patients would have otherwise been missed if the patients had only received the standard-of-care rapid antibody test. Curbing HIV incidence in the United States will require multiple innovative approaches. Detecting acute infections through 4th generation testing is one of the many valuable tools that organizations can utilize in the new decade. Key words: Acute HIV infection, testing algorithms, linkage to care, HIV antigen and antibody combination test, HIV antigen and antibody combination test, Abbott Architect.

Ability of Alere™ HIV Combo to diagnose acute HIV infection is based mainly on HIV-1 p24 antigen detection.

Alere™ HIV Combo is the only rapid and sensitive point-of-care 4th generation (antigen/antibody) HIV test newly available in Thailand which is advantageous of differentiating between positivity of antigen or antibody or both, especially in acute HIV infection (AHI). AHI in this study was defined by positive machine-based 4th generation test with measurable HIV-RNA but negative 3rd generation (IgM/IgG antibody only) tests. To evaluate the performance characteristics of Alere™ HIV Combo. Fifty stored plasma samples of subjects diagnosed with AHI were used to evaluate Alere™ HIV Combo. Of the 50 AHI samples, Alere™ HIV Combo was positive in 37 (74%): 5 with antibody positive only (R1), 26 with p24 antigen positive only (R2), and 6 with both p24 antigen and antibody positive (R3). Mean sample/cut-off (S/ CO) ratios from machine-based 4th generation test of R1, R2 and R3 were 21.55, 148.38 and 72.97 respectively as compared to 7.57 for the 13 non-reactive (NR) samples. The corresponding median log10 HIV-RNA of NR, R1, R2 and R3 were 5.59, 5.86, 7.00 and 6.61 copies/mL respectively. R2 and R3 had significantly higher S/CO and HIV-RNA than NR and R1. Alere™ HIV Combo detected mainly p24 antigen in AHI as seen in 32/50 (64%) subjects and could detect 11/50 (22%) antibody in AHI samples which were missed by the two 3rd generation HIV tests used in our testing algorithm. Alere™ HIV Combo is the ideal screening test in a setting with high AHI where machine-based 4th generation test is not available.

LB-6. Increased Diagnoses of Acute HIV Infection through Routine ED Screening and Rapid Linkage to Care and initiation of HAART During the COVID-19 Pandemic

BackgroundThe COVID-19 pandemic has negatively impacted routine HIV screening in healthcare settings. This has serious implications, especially for patients with acute HIV infection (AHI) presenting with symptoms suggesting COVID-19 infection. This is a high priority population for rapid linkage to care (LTC) and initiation of HAART.MethodsWe reviewed data from our eXpanded HIV Testing and LTC (X-TLC) Program, a collaboration effort between 13 healthcare centers on the South and West Sides of Chicago. Since 2016, most sites had 4th or 5th generation HIV Ag/Ab testing available.ResultsMost sites experienced reductions in HIV screens during the COVID-19 pandemic. Advanced planning by our ED incorporated blood draws for HIV screens as part of COVID-19 evaluations. UCM performed 19,111 HIV screens (11,133 in the ED) between 1/1/20 and 8/17/20, along with 100,635 COVID PCRs (14,754 in ED) between 3/17/20 and 8/17/20. Nine patients were diagnosed with AHI after the first case of COVID-19 in Chicago (1/24/20), and 7 were diagnosed after the first case of community transmission in Cook County (3/8/20). All cases of AHI were diagnosed in the ED. The rate of AHI was significantly higher in 2020 versus the prior 4 years (14.4 vs 6.8 per year, p < 0.05). AHI patients comprised 25.7 % (9/35) of all new diagnoses, the highest percent ever. There were 7 men (6 identified as MSM) and 2 cis-gender women, median age of 25 years (21 to 28 years). The median viral load was 6 million (115,000 to > 6 million) copies/mL. Eight of 9 patients presented with an illness indistinguishable from COVID-19, including 1co-infected patient. All were LTC and started on HAART from time of PCR result within a median of 1 day (0–38), but 3 days (range 1–41) from sample collection as a result of delayed reflex PCR confirmatory testing due to high demands on lab personnel and scarcity of reagents due to COVID-19 PCR volumes (since resolved).HIV Screening and COVID-19 Testing in the ED During COVID-19 ConclusionContinued HIV screening in our ED during the COVID-19 pandemic identified an increased number of patients with AHI. These individuals may be more likely to present for care due to fear of COVID-19 infection. We achieved rapid LTC and initiation of HAART without any incremental increases in resources. All HIV screening programs should incorporate blood-based HIV screening into their COVID-19 testing programs.Disclosures Moira McNulty, MD, MS, Gilead Sciences (Grant/Research Support)

HIV Prevalence among Meical Inward Patients in the National Hospital of Sri Lanka (NHSL) with the Assessment of Patient Acceptance, the Feasibility and Challenges of the Hospital Based Rapid HIV Diagnostic Test

<strong>Introduction: </strong>Hospital based HIV Rapid Diagnostic Testing (RDT) was introduced in 2018, following programmatic decision. However, being the province with the highest HIV prevalence in the country, the number of hospital based rapid testing carried out in Western province was not impressive, leading to missed opportunities and late diagnosis. Therefore, RDT was re-implemented in selected medical wards of NHSL. <strong> </strong> <strong>Objective: </strong>To assess the case detection rate, the feasibility and challenges of the rapid HIV testing services among inpatients of medical wards of NHSL. <strong> </strong> <strong>Method: </strong>A descriptive demonstration study, carried out among consecutive 3,395 new admissions to selected medical wards of the NHSL within three months period. HIV status was tested on finger prick blood, using FDA and WHO approved 4th generation HIV RDT (with 100% sensitivity, 99.7% specificity) following informed consent. Patient information were extracted from bed head tickets. Focus Group Discussions (FGD) were carried out with the relevant hospital staff to assess the challenges. Confidentiality of patients ensured by training all the health care workers involved in RDT and followed up of the positive test results, according to the national guidelines <strong> </strong> <strong>Results: </strong>Among the 3395 participants, eight (8) were found to be positive, with the HIV prevalence of 0.23 %. The patient acceptance rate was 96%. Out of the positives, majority were males (n=6) and married (n=5) and half of them were from the Colombo district. Only two (25 %) had AIDS defining symptoms while the majority (n=5) had baseline CD4 count less than 200 cells/μl . Work overload, consent taking, lack of confidence in post-test HIV counselling were identified as major areas of concern. <strong> </strong> <strong>Conclusions: </strong>Hospital-based HIV rapid testing is one of the high yielding programmatic strategies implemented in the country so far. The positivity rate of the study sample was 0.23% which is higher than the HIV positivity rate reported through different testing strategies including the general public (0.03%), and STD samples (0.1%). Further, beating up the challenge of missed opportunities and late diagnosis was highlighted. Therefore, addressing the identified barriers through policy and administrative support and further scaling up of hospital-based HIV testing is highly recommended.

Universal HIV and Birth Cohort HCV Screening in San Diego Emergency Departments

Universal HIV and HCV screening in emergency departments (ED) can reach populations who are less likely to get tested otherwise. The objective of this analysis was to evaluate universal opt-out HIV and HCV screening in two EDs in San Diego. HIV screening for persons aged 13–64 years (excluding persons known to be HIV+ or reporting HIV testing within last 12 months) was implemented using a 4th generation HIV antigen/antibody assay; HCV screening was offered to persons born between 1945 and 1965. Over a period of 16 months, 12,575 individuals were tested for HIV, resulting in 33 (0.26%) new HIV diagnoses, of whom 30 (90%) were successfully linked to care. Universal screening also identified 74 out-of-care for >12-months HIV+ individuals of whom 50 (68%) were successfully relinked to care. Over a one-month period, HCV antibody tests were conducted in 905 individuals with a seropositivity rate of 9.9% (90/905); 61 seropositives who were newly identified or never treated for HCV had HCV RNA testing, of which 31 (51%) resulted positive (3.4% of all participants, including 18 newly identified RNA positives representing 2% of all participants), and 13/31 individuals (42%) were linked to care. The rate of newly diagnosed HCV infections exceeded the rate of newly diagnosed HIV infections by >7-fold, underlining the importance of HCV screening in EDs.

Risk stratification of HIV infection for patients needing molecular confirmation with the Abbott 4th generation Architect System

BackgroundSome patients need their 4th generation HIV testing results confirmed with molecular testing after primary confirmatory testing which may not be immediately available. Further risk stratification of these patients pending the results of molecular testing may be of value not only for patient counseling but also for treatment of women in labor. ObjectivesTo determine the risk of a positive test result on molecular testing for these patients. Study designThe risk of a positive molecular test result for patients with a result needing molecular confirmation on a 4th generation HIV testing algorithm (Abbott Architect, Multispot/Geenius confirmatory test) was stratified based on the patient’s white blood cell (WBC) count and the magnitude of Architect result Signal Cut Off ratio (S/CO). ResultsA total of 61,666 patients were tested with 658 (1.1%) positive results and 76 (0.12%) patients needing molecular confirmation. Patients with an S/CO of <5 or an S/CO of 5–100 with a WBC > 6.5 × 10 9 cells/l had a significantly lower risk of a positive molecular HIV test (0/48, 0%) than patients with an S/CO 5–100 with a WBC < 6.0 s × 10 9 cells/l (5/9, 56%, p < .001) or an S/CO > 100 (2/2, 100%, p < .001). Pregnant women had a significantly lower rate of positive test results (24/6924, 0.4%) than non-pregnant patients (634/54742, 1.1%, p < 0.001). All 12 cases needing molecular confirmation in pregnant women had negative NAT test results. ConclusionsPatients who need their HIV results confirmed with molecular testing using a 4th generation algorithm that includes the Abbott Architect System can be further stratified into low, intermediate, and high risk groups based on additional laboratory information pending the results of molecular testing. This risk stratification may be of value for patient counseling and treatment of women in labor.

859: 4th generation HIV testing in pregnancy: How sure is sure?

859: 4th generation HIV testing in pregnancy: How sure is sure?

Evaluation of two 4th generation point-of-care assays for the detection of Human Immunodeficiency Virus infection.

BackgroundFourth generation assays detect simultaneously antibodies for HIV and the p24 antigen, identifying HIV infection earlier than previous generation tests. Previous studies have shown that the Alere Determine HIV-1/2 Combo has lower than anticipated performance in detecting antibodies for HIV and the p24 antigen. Furthermore, there are currently very few studies evaluating the performance of Standard Diagnostics BIOLINE HIV Ag/Ab Combo.ObjectiveTo evaluate the performance of the Alere Determine HIV-1/2 Combo and the Standard Diagnostics BIOLINE HIV Ag/Ab Combo in a panel of frozen serum samples.Study designThe testing panel included 133 previously frozen serum specimens from the UCLA Clinical Microbiology & Immunoserology laboratory. Reference testing included testing for HIV antibodies by a 3rd generation enzyme immunoassay followed by HIV RNA detection. Antibody negative and RNA positive sera were also tested by a laboratory 4th generation HIV Ab/Ag enzyme immunoassay.ResultsReference testing yielded 97 positives for HIV infection and 36 negative samples. Sensitivity of the Alere test was 95% (88–98%), while the SD Bioline sensitivity was 91% (83–96%). Both assays showed 100% (90–100%) specificity. No indeterminate or invalid results were recorded. Among 13 samples with acute infection (HIV RNA positive, HIV antibody negative), 12 were found positive by the first assay and 8 by the second. The antigen component of the Alere assay detected 10 acute samples, while the SD Bioline assay detected only one.ConclusionsBoth rapid assays showed very good overall performance in detecting HIV infection in frozen serum samples, but further improvements are required to improve the performance in acute infection.

The Importance of 4th Generation HIV Testing in an Urban Emergency Department

Early Acute Human Immunodeficiency Virus Infection (eAHI) diagnosis, via 4th generation testing methodology, presents an opportunity for earlier detection and immediate linkage to care for infected persons. We report on two patients with high-risk behaviors for HIV infection, presenting with atypical symptoms of eAHI in an urban Emergency Department (ED). This case report should raise the index of suspicion for HIV among ED physicians as well as underscore the importance of reducing HIV transmission through earlier detection. Universal screening of patients aged 13–64, incorporating new HIV diagnostic algorithms, is recommended by the Centers for Disease Control and Prevention (CDC). By employing the 4th generation HIV testing methodology, we can potentially diagnose HIV infection earlier compared to older testing methodologies. Currently, 3rd generation HIV testing is used to detect the presence of HIV antibodies, generally through an enzyme-linked immunosorbent assay (ELISA). However, detection of HIV antibodies can take anywhere from 3 to 12 weeks, depending on the individual and testing modality used. This newer diagnostic paradigm enables earlier identification of newly infected individuals. Early HIV detection allows for linkage to care and the administration of effective treatment modalities shortly thereafter. As HIV transmission is highest during its initial acquisition, early detection and linkage to care has been shown to be an efficient method to decrease transmission through subsequent changes in behaviors of those infected.

Contamination with HIV antibody may be responsible for false positive results in specimens tested on automated platforms running HIV 4th generation assays in a region of high HIV prevalence.

IntroductionIn South Africa where the prevalence of HIV infection is very high, 4th generation HIV antibody/p24 antigen combo immunoassays are the tests of choice for laboratory based screening. Testing is usually performed in clinical pathology laboratories on automated analysers. To investigate the cause of false positive results on 4th generation HIV testing platforms in public sector laboratories, the performance of two automated platforms was compared in a clinical pathology setting, firstly on routine diagnostic specimens and secondly on known sero-negative samples.MethodsFirstly, 1181 routine diagnostic specimens were sequentially tested on Siemens and Roche automated 4th generation platforms. HIV viral load, western blot and follow up testing were used to determine the true status of inconclusive specimens. Subsequently, known HIV seronegative samples from a single donor were repeatedly tested on both platforms and an analyser was tested for surface contamination with HIV positive serum to identify how suspected specimen contamination could be occurring.ResultsSerial testing of diagnostic specimens yielded 163 weakly positive or discordant results. Only 3 of 163 were conclusively shown to indicate true HIV infection. Specimen contamination with HIV antibody was suspected, based on the following evidence: the proportion of positive specimens increased on repeated passage through the analysers; viral loads were low or undetectable and western blots negative or indeterminate on problem specimens; screen negative, 2nd test positive specimens tested positive when reanalysed on the screening assay; follow up specimens (where available) were negative. Similarly, an increasing number of known negative specimens became (repeatedly) sero-positive on serial passage through one of the analysers. Internal and external analyser surfaces were contaminated with HIV serum, evidence that sample splashes occur during testing.ConclusionsDue to the extreme sensitivity of these assays, contamination with minute amounts of HIV antibody can cause a negative sample to test positive. Better contamination control measures are needed on analysers used in clinical pathology environments, especially in regions where HIV sero-prevalence is high.

Comparison of turnaround time and total cost of HIV testing before and after implementation of the 2014 CDC/APHL Laboratory Testing Algorithm for diagnosis of HIV infection

BackgroundUpdated recommendations for HIV diagnostic laboratory testing published by the Centers for Disease Control and Prevention and the Association of Public Health Laboratories incorporate 4th generation HIV immunoassays, which are capable of identifying HIV infection prior to seroconversion. ObjectivesThe purpose of this study was to compare turnaround time and cost between 3rd and 4th generation HIV immunoassay-based testing algorithms for initially reactive results. Study DesignThe clinical microbiology laboratory database at Mayo Clinic, Rochester, MN was queried for 3rd generation (from November 2012 to May 2014) and 4th generation (from May 2014 to November 2015) HIV immunoassay results. All results from downstream supplemental testing were recorded. Turnaround time (defined as the time of initial sample receipt in the laboratory to the time the final supplemental test in the algorithm was resulted) and cost (based on 2016 Medicare reimbursement rates) were assessed. ResultsA total of 76,454 and 78,998 initial tests were performed during the study period using the 3rd generation and 4th generation HIV immunoassays, respectively. There were 516 (0.7%) and 581 (0.7%) total initially reactive results, respectively. Of these, 304 (58.9%) and 457 (78.7%) were positive by supplemental testing. There were 10 (0.01%) cases of acute HIV infection identified with the 4th generation algorithm. The most frequent tests performed to confirm an HIV-positive case using the 3rd generation algorithm, which were reactive initial immunoassay and positive HIV-1 Western blot, took a median time of 1.1 days to complete at a cost of $45.00. In contrast, the most frequent tests performed to confirm an HIV-positive case using the 4th generation algorithm, which included a reactive initial immunoassay and positive HIV-1/-2 antibody differentiation immunoassay for HIV-1, took a median time of 0.4 days and cost $63.25. Overall median turnaround time was 2.2 and 1.5 days, and overall median cost was $63.90 and $72.50 for 3rd and 4th generation algorithms, respectively. ConclusionsBoth 3rd and 4th generation HIV immunoassays had similar total numbers of tests performed and positivity rates during the study period. A greater proportion of reactive 4th generation immunoassays were confirmed to be positive, and the 4th generation algorithm identified several cases of acute HIV infection that would have been missed by the 3rd generation algorithm. The 4th generation algorithm had a more rapid turnaround time but higher cost for confirmed positive HIV infections and overall, compared to the 3rd generation algorithm.

Clinical validation of a novel diagnostic HIV-2 total nucleic acid qualitative assay using the Abbott m2000 platform: Implications for complementary HIV-2 nucleic acid testing for the CDC 4th generation HIV diagnostic testing algorithm

BackgroundThe 2014 CDC 4th generation HIV screening algorithm includes an orthogonal immunoassay to confirm and discriminate HIV-1 and HIV-2 antibodies. Additional nucleic acid testing (NAT) is recommended to resolve indeterminate or undifferentiated HIV seroreactivity. HIV-2 NAT requires a second-line assay to detect HIV-2 total nucleic acid (TNA) in patients’ blood cells, as a third of untreated patients have undetectable plasma HIV-2 RNA. ObjectivesTo validate a qualitative HIV-2 TNA assay using peripheral blood mononuclear cells (PBMC) from HIV-2–infected Senegalese study participants. Study designWe evaluated the assay precision, sensitivity, specificity, and diagnostic performance of an HIV-2 TNA assay. Matched plasma and PBMC samples were collected from 25 HIV-1, 30 HIV-2, 8 HIV-1/-2 dual-seropositive and 25 HIV seronegative individuals. Diagnostic performance was evaluated by comparing the outcome of the TNA assay to the results obtained by the 4th generation HIV screening and confirmatory immunoassays. ResultsAll PBMC from 30 HIV-2 seropositive participants tested positive for HIV-2 TNA including 23 patients with undetectable plasma RNA. Of the 30 matched plasma specimens, one was HIV non-reactive. Samples from 50 non-HIV-2 infected individuals were confirmed as non-reactive for HIV-2 Ab and negative for HIV-2 TNA. The agreement between HIV-2 TNA and the combined immunoassay results was 98.8% (79/80). Furthermore, HIV-2 TNA was detected in 7 of 8 PBMC specimens from HIV-1/HIV-2 dual-seropositive participants. ConclusionsOur TNA assay detected HIV-2 DNA/RNA in PBMC from serologically HIV-2 reactive, HIV indeterminate or HIV undifferentiated individuals with undetectable plasma RNA, and is suitable for confirming HIV-2 infection in the HIV testing algorithm.

Multi-centre field evaluation of the performance of the Trinity Biotech Uni-Gold HIV 1/2 rapid test as a first-line screening assay for gay and bisexual men compared with 4th generation laboratory immunoassays

BackgroundThe Trinity Biotech Uni-Gold HIV test (Uni-Gold) is often used as a supplementary rapid test in testing algorithms. ObjectiveTo evaluate the operational performance of the Uni-Gold as a first-line screening test among gay and bisexual men (GBM) in a setting where 4th generation HIV laboratory assays are routinely used. Study designWe compared the performance of Uni-Gold with conventional HIV serology conducted in parallel among GBM attending 22 testing sites. Sensitivity was calculated separately for acute and established infection, defined using 4th generation screening Ag/Ab immunoassay (EIA) and Western blot results. Previous HIV testing history and results of supplementary 3rd generation HIV Ab EIA, and p24 antigen EIA were used to further characterise cases of acute infection. ResultsOf 10,793 specimens tested with Uni-Gold and conventional serology, 94 (0.90%, 95%CI:0.70–1.07) were confirmed as HIV-positive by conventional serology, and 37 (39.4%) were classified as acute infection. Uni-Gold sensitivity was 81.9% overall (77/94, 95%CI:72.6–89.1); 56.8% for acute infection (21/37, 95%CI:39.5–72.9) and 98.2% for established infection (56/57, 95%CI:90.6–100.0). Of 17 false non-reactive Uni-Gold results, 16 were acute infections, and of these seven were p24 antigen reactive but antibody negative. Uni-Gold specificity was 99.9% (10,692/10,699, 95%CI:99.9–100.0), PPV was 91.7% (95%CI:83.6–96.6) and NPV was 99.8% (95%CI:99.7–99.9), respectively. ConclusionsIn this population, Uni-Gold had good specificity and sensitivity was high for established infections when compared to 4th generation laboratory assays, however sensitivity was lower in acute infections. Where rapid tests are used in populations with a high proportion of acute infections, additional testing strategies are needed to detect acute infections.

388 Implementation of an Emergency Department Syphilis and HIV Point-of-Care Screening Process During an Outbreak of Syphilis in Detroit, MI in Collaboration With the Infectious Disease Department and the Centers for Disease Control and Prevention

The number of primary and secondary syphilis cases in Detroit, Michigan increased from 73 in 2010 to 199 to 2013. Cases were predominantly in young African American men with who have sex with men and with had a high rate of HIV co-infection. The infectious disease (ID) department at Henry Ford Hospital (HFH), in collaboration with the Centers for Disease Control and Prevention (CDC) determined the emergency department (ED) would be the optimal setting to implement a screening program. Young men in Detroit are typically non-health care seeking; however, EDs are venues they do frequent when they access the health care system. We hypothesized that the implementation of an ED screening model would detect an increased number of syphilis and HIV cases than were seen with standard care. Point-of-care (POC) testing would allow presumptive treatment of active syphilis cases in the emergency department, whereas traditional testing would not typically result and allow for care within a typical ED visit time frame. Syphilis and HIV screening was offered to men aged 18-34 years seen in the HFH ED with an Emergency Severity Index (ESI) of 2-5. Dedicated, non-ED staff employed 2 rapid finger-stick POC tests: the Alere Determine HIV-1/2 Ag/ab Combo test (Determine) and the Syphilis Heath Check (SHC) treponemal tests. Participants also underwent venipuncture for standard lab-based testing for HIV and syphilis. Screening took place from 7:30am to 5pm, Monday through Friday. Patients were first approached by screeners, typically before the initial clinician contact and were offered screening. Confirmatory lab-based testing using the Biorad 4th generation HIV test, RPR, and TPPA tests were drawn in conjunction with ED nursing staff during their routine bloodwork. ED clinicians were notified of positive SHC POC testing and patients were treated presumptively in the ED. From 6/10/2015 to 3/11/2016, 871 patients were enrolled. Active syphilis (RPR + TPPA +) was identified in 6 (0.7%) participants, and newly diagnosed HIV in 7 (0.8%). There was one case of syphilis-HIV coinfection, and the combined prevalence was 1.4%. Three patients were treated in the ED for syphilis based on their POC testing results without treatment complications. The implementation of an ED syphilis and HIV POC screening program is a feasible method to detect new cases of disease. The screening process can be incorporated into ED patient flow and provide clinicians with immediate test results to determine the need for treatment. POC HIV and syphilis testing are particularly important to ED providers, who may not otherwise receive important test results for their patients before they leave the emergency department.

Comparison of 4th-Generation HIV Antigen/Antibody Combination Assay With 3rd-Generation HIV Antibody Assays for the Occurrence of False-Positive and False-Negative Results

Comparison of 4th-Generation HIV Antigen/Antibody Combination Assay With 3rd-Generation HIV Antibody Assays for the Occurrence of False-Positive and False-Negative Results

1536Seek and Ye Shall Find: Successful Implementation of Hospital Laboratory-based 4th Generation HIV Screening

1536Seek and Ye Shall Find: Successful Implementation of Hospital Laboratory-based 4th Generation HIV Screening