Sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays or HIV RNA tests

Rapid tests should be used with caution for HIV-1 primary infection screening

Rapid tests allow outpatient, low cost, reliable, screening for chronic HIV infection. However, data regarding their sensitivity on primary infection remain scarce. The objective of this study was to assess sensitivity of nine HIV rapid tests for primary HIV-1 infection screening. Seventy-five serum samples from patients during HIV-1 primary infection were included. Primary infection was diagnosed by a positive 4th generation ELISA and HIV-1 RNA positivity confirmed by Western blot patterns associated with HIV-1 primary infection. Early seroconversion was defined as the absence of antibodies on HIV-1 Western blot associated with HIV-1 RNA and p24-antigen positivity. An identical sensitivity (95% CI) of 76.7% (65.2-84.2%) was observed for HIV 1/2 STAT-PAK® Assay (STAT-PAK), INSTI™ HIV-1/HIV-2 antibody Test (INSTI), SURE CHECK® HIV 1/2 (SURE CHECK) and MULTISURE HIV rapid test (MULTISURE) with visual reading. Sensitivity was 74.7% (63.8-83.1%) for MULTISURE (automatic reading), 77.0% (66.3-85.1%) for FIRST RESPONSE® Test VIH 1-2.O CARTE (FIRST RESPONSE), 83.8% (73.8-90.5%) for VIKIA HIV1/2® (VIKIA), 88.0% (78.7-93.6%) for Genie™ Fast HIV 1/2 (Genie Fast), 88.6% (79.0-94.1%) for Hexagon HIV (Hexagon), and 92.8% (83.6-96.3%) for Exacto® TEST HIV Pro (Exacto). However, rapid tests performed poorly for the early seroconversion subgroup (n = 14), with sensitivities ranging from 7% (1.3-31.5%) for STAT-PAK, INSTI, SURE CHECK, MULTISURE (automatic reading), to 29% (12-55%) for FIRST RESPONSE, 31% (13-58%) for VIKIA, 43% (21-67%) for Hexagon and 57.1% (32.6-78.6%) for Exacto and Genie Fast. Overall, despite significant discrepancies in sensitivity, HIV rapid tests should be used with caution in the context of a suspected primary infection.

Development of a LAMP-Based Diagnostic for the Detection of Multiple HIV-1 Strains

Since its first appearance in 1981, HIV-1 has remained a global concern. Current methods for diagnosing HIV-1, while effective, are mostly specific to a given subtype of HIV-1 and often require expensive equipment and highly trained individuals to collect and process the sample. It is necessary to develop a sensitive diagnostic method that can be administered with minimal equipment to provide better care in low-resource settings. Loop-mediated isothermal amplification is a rapid and sensitive method for detecting the presence of specific nucleic acid sequences. Herein we report the development and comparison of two different HIV LAMP assays, integrase and VPR, as well as the comparison between TRIZol and magnetic beads RNA extraction methods for each assay. Our analysis shows that the integrase assay was able to detect the virus from multiple subtypes in under 30 min with a variable limit of detection (LOD) that was dependent on the HIV-1 subtype.

High level of HIV viral suppression in a cross-sectional study of Ugandan men with urethritis and bacterial STI

BACKGROUND

Urethritis associated with non-viral sexually transmitted infections (STI) increases the risk of HIV acquisition and transmission in those living with HIV (LWH) without viral load suppression (VLS). Compared to women, men typically have lower rates of HIV VLS. We assessed the prevalence of VLS and drug resistance mutations in men LWH and urethral discharge syndrome (UDS) in Kampala, Uganda.

METHODS

Men with UDS were recruited in Kampala October 2019-November 2020. Medical, demographic, and behavioural data were collected with biological samples. All reactive HIV results (rapid, sequential algorithm) underwent confirmatory HIV antibody- and HIV incidence-testing, and viral load (VL) measurement. The pol and gp41 regions were sequenced on samples with VLs >1000 cpm, phylogenetic trees were generated, and resistance mutations were investigated.

RESULTS

50 of 250 participants (20%) had reactive HIV rapid tests and 48/50 (96%) were aware of their HIV status and using antiretroviral therapy (ART). The median age was 38 years (IQR 32-45), 27/50 (54%) had engaged in transactional sex, and 30/50 (60%) reported alcohol before sex. VLS was present in 46/50 (92%). There were no major resistance mutations present in any samples analyzed.

CONCLUSIONS

The prevalence of HIV and VLS was greater in these men than in the general Ugandan adult population. Most men LWH were on ART and thus less likely to transmit HIV despite demonstrating sexual behaviours associated with high-risk of STIs. These data emphasize that high levels of ART coverage and VLS are achievable among men with UDS in urban Kampala.

Acute Babesiosis Causing a False-Positive HIV Result: An Unexpected Association

Babesiosis is a tick-borne condition that causes hemolytic anemia and manifests with flu-like symptoms such as fevers, chills, fatigue, and anorexia. Very few case reports have documented babesiosis infection associated with a false-positive HIV test. In this case report, we add to the current literature by describing a patient admitted for treatment of babesiosis who had a preliminary positive HIV test on admission and a negative repeat HIV test after one week of treatment for babesiosis. A 60-year-old male with a past medical history of high cholesterol presented to the Emergency Department after having abnormal laboratory tests with his primary care doctor. He reported fever, fatigue, anorexia, and worsening jaundice for three weeks. He was hypotensive and febrile on admission. A blood smear showed Babesia species with 1-2% infected red blood cells. He was admitted to the intensive care unit and received treatment with plasmapheresis, atovaquone, and antibiotics. The fourth-generation HIV 1/2 antigen/antibody test was initially positive but after treatment, HIV testing was negative. A misdiagnosis of HIV can greatly impact a patient's quality of life as antiretroviral therapy has multiple deleterious side effects. Clinicians must consider further evaluation of patients with acute babesiosis who also test positive for HIV.

Point-of-Care Testing for Sexually Transmitted Infections

Point-of-care testing for sexually transmitted infections is essential for controlling transmission and preventing sequelae in high-risk populations. Since the World Health Organization published the ASSURED criteria, point-of-care testing has improved for use in large population screening and rapid testing that prevents loss of clinical follow-up. Recent advancements have been advantageous for low-resource areas allowing testing at a minimal cost without reliable electricity or refrigeration. Point-of-care nucleic acid detection and amplification techniques are recommended, but are often inaccessible in low-resource areas. Future advancements in point-of-care diagnostic testing should focus on improving antibody-based assays, monitoring viral loads, and detecting antimicrobial resistance.

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

BACKGROUND

HIV 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.

METHODS

Participants 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.

RESULTS

Initial 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.

CONCLUSIONS

Self-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.

Influence of Combination Antiretroviral Therapy on HIV-1 Serological Responses and Their Implications: A Systematic Review and Meta-Analysis

We aimed to analyze HIV-1 seroreversion caused by combination antiretroviral therapy (cART) and to explore antibody levels of anti-HIV-1 as an alternative biomarker of HIV-1 reservoir. We searched PubMed, Embase, the Cochrane Library, and Web of Science up to August 2021 for publications about the performance of HIV-1 serological assays or the association between antibody responses against HIV-1 and HIV-1 reservoirs. Potential sources of heterogeneity were explored by meta-regression analysis, including the year of publication, country, pretreatment viral load, sample size, the timing of treatment, time on cART, and principle or type of serological assay. Twenty-eight eligible studies with a total population of 1,883 were included in the meta-analysis. The pooled frequency of HIV-1 seronegativity is 38.0% (95% CI: 28.0%–49.0%) among children with vertical HIV-1 infection and cART initiation at the age of less than 6 months, while the percentage of HIV-1 seronegativity declined to 1.0% (95% CI: 0%–3.0%) when cART was initiated at the age of >6 months. For adult patients, 16.0% (95% CI: 9.0%–24.0%) of them were serologically negative when cART was initiated at acute/early infection of HIV-1, but the seronegative reaction was rarely detected when cART was started at chronic HIV-1 infection. Substantial heterogeneity was observed among the studies to estimate the frequency of HIV-1 seronegativity in the early-cART population (I² ≥ 70%, p < 0.05 and all), while mild heterogeneity existed for the deferred-cART subjects. Moreover, anti-HIV-1 antibody response positively correlates with HIV-1 reservoir size with a pooled rho of 0.43 (95% CI: 0.28–0.55), suggesting that anti-HIV antibody level may be a feasible biomarker of HIV-1 reservoir size.

Evaluation of serological assays for the diagnosis of HIV infection in adults

Serological tests based on the enzyme immunoassay (EIA) are the primary tool for the diagnosis of human immunodeficiency virus (HIV) in adults and have rapidly evolved to quicker, affordable and more accurate test formats to detect early HIV infection. Second- and third-generation HIV rapid tests detect the immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies to the HIV and are used at the point of care and in HIV self-testing. The tests are affordable and accessible in state and private diagnostic laboratories. The present-day fourth- and fifth-generation EIAs can detect both p24 antigen and IgG and IgM HIV antibodies and thereby diagnose early HIV infection at approximately 2 weeks. The fourth- and fifth-generation EIAs also report sensitivity and specificity of more than 99%. The correct interpretation of HIV diagnosis of false-positive and false-negative EIA test results requires collaborative scrutiny of patient factors and laboratory test methodologies.

HIV-1 diagnosis using dried blood spots from patients in Kinshasa, DRC: a tool to detect misdiagnosis and achieve World Health Organization 2030 targets

INTRODUCTION

Currently, only 54% of the population of the Democratic Republic of the Congo (DRC) know their HIV status. The aim of this study was to detect HIV misdiagnosis from rapid diagnostic tests (RDT) and to evaluate serological immunoassays using dried blood spots (DBS) from patients in Kinshasa, DRC.

METHODS

Between 2016 and 2018, 365 DBS samples were collected from 363 individuals and shipped to Spain. The samples were from people with a new HIV positive (n = 123) or indeterminate (n = 23) result, known HIV-positive patients (n = 157), and a negative control group (n = 62). HIV serology was performed using Elecsys HIV combi PT (Roche), VIDAS HIV Duo Quick (BioMérieux), and Geenius (Bio-Rad). In addition, HIV RNA detection was performed in all samples using the COBAS AmpliPrep/COBAS Taqman HIV-1 Test 2.0 (Roche).

RESULTS

Overall, 272 samples were found to be positive and 93 to be negative for HIV serology. The sensitivity was 100% for both Elecsys and VIDAS techniques, but specificity was slightly higher for the VIDAS test: 100% (96.1-100%) vs 98.9% (94.1-99.9%). Of the 23 indeterminate cases using RDT, only three cases were true-positives with a detectable viral load. Eleven samples out of the 280 classified as positive by RDT corresponded to nine patients who had received a false diagnosis of HIV through RDT (3.9%); six of them had been on antiretroviral therapy for at least 2 years.

CONCLUSIONS

Elecsys HIV combi PT and VIDAS HIV Duo Quick immunoassays showed high sensitivity and specificity when using DBS. RDT-based serological diagnosis can lead to HIV misdiagnosis with personal and social consequences in sub-Saharan Africa.

Label-free aptasensor for p24-HIV protein detection based on graphene quantum dots as an electrochemical signal amplifier

Human immunodeficiency virus (HIV) is still considered a pandemic, and the detection of p24-HIV protein has an important role in the early diagnosis of HIV in adults and newborns. The accessibility of these trials depends on the price and execution difficulty of the method, which can be reduced using electrochemical methods by using enzymeless approaches, disposable and accurate devices. In this work, graphene quantum dots were acquired by a simple synthesis and employed as an electrochemical signal amplifier and support for the aptamer immobilization through a feasible and stable modification of disposable screen-printed electrodes. The device has been easily assembled and used to detect p24-HIV protein without the interference of similar proteins or sample matrix. Using the best set of experimental conditions, a linear correlation between analytical signal and log of p24-HIV concentration from 0.93 ng mL^-1 to 93 μg mL^-1 and a limit of detection of 51.7 pg mL^-1 were observed. The developed device was applied to p24 determination in spiked human serum and provided distinct levels of signal for positive and negative samples, successfully identifying real samples with the target protein. This sensor is a step towards the development of point-of-care devices and the popularization of electrochemical methods for trials and diagnostics of relevant diseases.

Use of penile plethysmography in the court: A review of practices in Canada, the United Kingdom and the United States

Penile plethysmography (PPG) is an objective measure of male sexual arousal in response to the presentation of a series of erotic and neutral stimuli. This measure is now widely recognized as the most reliable means of objectively measuring male sexual arousal to specific stimuli. Many clinicians and researchers consider PPG to be a vital contribution to the assessment and treatment of adult men with paraphilic interests and men who have committed sex crimes. PPG contributes to the clinical assessment of paraphilic interests, appraisal of risk of recidivism, and provides an objective measurement of changes in sexual arousal in response to treatment. There is strong support for the utility of PPG within clinical and legal contexts. This article addresses ways in which PPG has been utilized in the courts as part of expert clinical opinion. History of its use, details regarding admissibility in court, and case law are explored within the legal systems of Canada, the UK and the USA. Support for the inclusion of PPG as expert evidence is provided and judicial misunderstandings on the rationale for PPG use and its clinical utility in forensic assessments are discussed.

Rapid diagnostic tests for infectious diseases in the emergency department

Background

Rapid diagnostic tests (RDTs) for infectious diseases, with a turnaround time of less than 2 hours, are promising tools that could improve patient care, antimicrobial stewardship and infection prevention in the emergency department (ED) setting. Numerous RDTs have been developed, although not necessarily for the ED environment. Their successful implementation in the ED relies on their performance and impact on patient management.

Objectives

The aim of this narrative review was to provide an overview of currently available RDTs for infectious diseases in the ED.

Sources

PubMed was searched through August 2019 for available studies on RDTs for infectious diseases. Inclusion criteria included: commercial tests approved by the US Food and Drug Administration (FDA) or Conformité Européenne (CE) in vitro diagnostic devices with data on clinical samples, ability to run on fully automated systems and result delivery within 2 hours.

Content

A nonexhaustive list of representative commercially available FDA- or CE-approved assays was categorized by clinical syndrome: pharyngitis and upper respiratory tract infection, lower respiratory tract infection, gastrointestinal infection, meningitis and encephalitis, fever in returning travellers and sexually transmitted infection, including HIV. The performance of tests was described on the basis of clinical validation studies. Further, their impact on clinical outcomes and anti-infective use was discussed with a focus on ED-based studies.

Implications

Clinicians should be familiar with the distinctive features of each RDT and individual performance characteristics for each target. Their integration into ED work flow should be preplanned considering local constraints of given settings. Additional clinical studies are needed to further evaluate their clinical effectiveness and cost-effectiveness.

Assessment of readiness to transition from antenatal HIV surveillance surveys to PMTCT programme data-based HIV surveillance in South Africa: The 2017 Antenatal Sentinel HIV Survey

OBJECTIVE

South Africa has used antenatal HIV surveys for HIV surveillance in pregnant women since 1990. We assessed South Africa's readiness to transition to programme data based antenatal HIV surveillance with respect to PMTCT uptake, accuracy of point-of-care rapid testing (RT) and selection bias with using programme data in the context of the 2017 antenatal HIV survey.

METHODS

Between 1 October and 15 November 2017, the national survey was conducted in 1,595 public antenatal facilities selected using stratified multistage cluster sampling method. Results of point-of-care RT were obtained from medical records. Blood samples were taken from eligible pregnant women and tested for HIV using immunoassays (IA) in the laboratory. Descriptive statistics were used to report on: PMTCT uptake; agreement between HIV point-of-care RT and laboratory-based HIV-1 IA; and selection bias associated with using programme data for surveillance.

RESULTS

PMTCT HIV testing uptake was high (99.8%). The positive percent agreement (PPA) between RT and IA was lower than the World Health Organization (WHO) benchmark (97.6%) at 96.3% (95% confidence interval (CI): 95.9%-96.6%). The negative percent agreement was above the WHO benchmark (99.5%), at 99.7% (95% CI: 99.6%-99.7%) nationally. PPA markedly varied by province (92.9%-98.3%). Selection bias due to exclusion of participants with no RT results was within the recommended threshold at 0.3%.

CONCLUSION

For the three components assessed, South Africa was close to meeting the WHO standard for transitioning to routine RT data for antenatal HIV surveillance. The wide variations in PPA across provinces should be addressed.

HIV Testing With and Without a Clinical Consultation Among Men Who Have Sex With Men: A Randomized Controlled Trial

BACKGROUND

Increasing the frequency of HIV testing among men who have sex with men (MSM) maximizes the preventive effect of antiretroviral therapy, by reducing time to diagnosis and treatment.

SETTING

Melbourne Sexual Health Centre, Australia.

METHODS

This randomized controlled trial evaluated whether access to testing, without seeing a clinician would increase testing frequency. MSM attending for HIV testing between July 2014 and April 2015 were randomized in 1:1 ratio to the intervention arm (access to HIV and syphilis testing at 300 pathology centers, without requiring consultations) or the control arm (consultation at every test), without blinding. The primary outcome was the incidence of HIV testing over 12 months.

RESULTS

Of 443 men referred, 422 were randomized, 3 HIV positives at baseline were excluded, and 419 were analyzed. Of 208 control, 202 (97.1%) and 200 (94.8%) of 211 intervention group members were followed to 12 months. The intervention group had 453 tests in 205.6 person-years, incidence rate was 2.2 (95% confidence interval [CI]: 2.0 to 2.4) tests per year. The control group had 432 tests during 204.0 person-years, incidence rate was 2.1 (95% CI: 1.9 to 2.3) tests per year, and incidence rate ratio was 1.04 (95% CI: 0.89 to 1.2; P = 0.63). The annual rate of consultations was as follows: intervention, 1.61 (95% CI: 1.44 to 1.79); controls, 2.12 (95% CI: 1.92 to 2.33); rate ratio, 0.76 (95% CI: 0.65 to 0.88; P = 0.0001). There was no difference in quality of life scores (P = 0.61).

CONCLUSIONS

MSM permitted HIV and syphilis testing outside of clinical consultations did not test more frequently than controls but had 24% fewer consultations, reducing service demand.

TRIAL REGISTRATION

ACTRN12614000760673.

Trends and predictors of recent HIV testing over 22 years among a clinic sample of men who have sex with men in South Australia

Increasing the frequency of HIV testing is crucial for effective HIV prevention and care. The aim of the present study was to determine whether there has been a change in HIV testing among men who have sex with men (MSM) at the South Australia Specialist Sexual Health (SASSH) clinic over the past two decades.

METHODS

Computerised medical records of MSM who attended the SASSH at their first visit between 1994 and 2015 were used to determine whether HIV testing had changed among MSM. First HIV tests in each calendar year and return tests within 12 months were analysed. Factors associated with recent HIV testing were also examined.

RESULTS

There were 24036 HIV tests conducted among 8163 individual MSM over the study period. The proportion of newly registered MSM who reported ever being tested for HIV declined (P_trend=0.030), the proportion who reported recent HIV testing did not change (P_trend=0.955) and the proportion who have had current HIV testing increased (P_trend=0.008). The proportion of MSM who returned to the clinic for HIV testing within 12 months did not change (P_trend >0.05), with less than 40% of MSM returning for HIV testing. Factors independently associated with recent HIV testing included MSM aged ≥20 years, (odds ratio (OR) 1.79; 95% confidence interval (CI) 1.53-2.10), higher education (OR 1.28; 95% CI 1.12-1.45), non-Caucasian (African OR 1.68; 95% CI 1.30-2.17), having multiple sex partners (OR 1.47; 95% CI 1.29-1.69), having had sex interstate (OR 1.61; 95% CI 1.42-1.82) or overseas (OR 1.53; 95% CI 1.33-1.76) and injecting drug use (OR 1.56; 95% CI 1.29-1.88).

CONCLUSIONS

HIV testing rate among MSM attending SASSH was suboptimal. New approaches are needed to increase the uptake and early detection of HIV infection among the high-priority MSM population.

Utility Of POC Xpert HIV-1 Tests For Detection-Quantification Of Complex HIV Recombinants Using Dried Blood Spots From Kinshasa, D. R. Congo

Point-of-Care (POC) molecular assays improve HIV infant diagnosis and viral load (VL) quantification in resource-limited settings. We evaluated POC performance in Kinshasa (Democratic Republic of Congo), with high diversity of HIV-1 recombinants. In 2016, 160 dried blood samples (DBS) were collected from 85 children (60 HIV-, 18 HIV+, 7 HIV-exposed) and 75 HIV+ adults (65 treated, 10 naive) at Monkole Hospital (Kinshasa). We compared viraemia with Cepheid-POC-Xpert-HIV-1VL and the non-POC-COBAS®AmpliPrep/COBAS®TaqMan®HIV-1-Testv2 in all HIV+, carrying 72.4%/7.2% HIV-1 unique/complex recombinant forms (URF/CRF). HIV-1 infection was confirmed in 14 HIV+ children by Cepheid-POC-Xpert-HIV-1Qual and in 70 HIV+ adults by both Xpert-VL and Roche-VL, identifying 8 false HIV+ diagnosis performed in DRC (4 adults, 4 children). HIV-1 was detected in 95.2% and 97.6% of 84 HIV+ samples by Xpert-VL and Roche-VL, respectively. Most (92.9%) HIV+ children presented detectable viraemia by both VL assays and 74.3% or 72.8% of 70 HIV+ adults by Xpert or Roche, respectively. Both VL assays presented high correlation (R2 = 0.89), but showing clinical relevant ≥0.5 log VL differences in 15.4% of 78 cases with VL within quantification range by both assays. This is the first study confirming the utility of Xpert HIV-1 tests for detection-quantification of complex recombinants currently circulating in Kinshasa.

p24 revisited: a landscape review of antigen detection for early HIV diagnosis

: Despite major advances in HIV testing, early detection of infection at the point of care (PoC) remains a key challenge. Although rapid antibody PoC and laboratory-based nucleic acid amplification tests dominate the diagnostics market, the viral capsid protein p24 is recognized as an alternative early virological biomarker of infection. However, the detection of ultra-low levels of p24 at the PoC has proven challenging. Here we review the landscape of p24 diagnostics to identify knowledge gaps and barriers and help shape future research agendas. Five hundred and seventy-four research articles to May 2018 that propose or evaluate diagnostic assays for p24 were identified and reviewed. We give a brief history of diagnostic development, and the utility of p24 as a biomarker in different populations such as infants, the newly infected, those on preexposure prophylaxis and self-testers. We review the performance of commercial p24 assays and consider elements such as immune complex disruption, resource-poor settings, prevalence, and assay antibodies. Emerging and ultrasensitive assays are reviewed and show a number of promising approaches but further translation has been limited. We summarize studies on the health economic benefits of using antigen testing. Finally, we speculate on the future uses of high-performance p24 assays, particularly, if available in self-test format.

The accuracy of HIV rapid testing in integrated bio-behavioral surveys of men who have sex with men across 5 Provinces in South Africa

We describe the accuracy of serial rapid HIV testing among men who have sex with men (MSM) in South Africa and discuss the implications for HIV testing and prevention.This was a cross-sectional survey conducted at five stand-alone facilities from five provinces.Demographic, behavioral, and clinical data were collected. Dried blood spots were obtained for HIV-related testing. Participants were offered rapid HIV testing using 2 rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using a third-generation enzyme immunoassay (EIA) and a fourth-generation EIA as confirmatory. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false-positive, and false-negative rates were determined.Between August 2015 and July 2016, 2503 participants were enrolled. Of these, 2343 were tested by RDT on site with a further 2137 (91.2%) having definitive results on both RDT and EIA. Sensitivity, specificity, positive predictive value, negative predictive value, false-positive rates, and false-negative rates were 92.6% [95% confidence interval (95% CI) 89.6-94.8], 99.4% (95% CI 98.9-99.7), 97.4% (95% CI 95.2-98.6), 98.3% (95% CI 97.6-98.8), 0.6% (95% CI 0.3-1.1), and 7.4% (95% CI 5.2-10.4), respectively. False negatives were similar to true positives with respect to virological profiles.Overall accuracy of the RDT algorithm was high, but sensitivity was lower than expected. Post-HIV test counseling should include discussions of possible false-negative results and the need for retesting among HIV negatives.

HIV Knowledge, Perceived Risk and Gender as Modulators of Salivary HIV Rapid Testing in African Americans

BACKGROUND

Of more than 1.2 million people in the United States (US) living with HIV infection, almost 1 in 8 (12.8%) are unaware of their infection. The introduction of a rapid HIV test using a saliva sample in 2004 made immediate results possible in community-based settings. Despite use of salivary rapid testing (SRT) over the last ten years, not enough is known about barriers to and acceptability of SRT among African Americans (AAs).

PURPOSE

The purpose of this study was to identify factors associated with SRT for HIV among AAs.

METHODS

A cross-sectional study was conducted with 329 AA men and women recruited from a sexually transmitted infection (STI) clinic.

RESULTS

Results of study showed that participants with higher AIDS knowledge (p<0.001) and problem-focused coping (p<0.003) tended to have higher likelihood for participation in testing. In terms of seeking medical help, participants with lower emotional-focused coping, lower risky behavior and higher AIDS knowledge tended to be more likely to seek medical help (p=0.015, p<0.001, p<0.04, respectively). Female participants with higher values of risky behavior tended to be more likely to participate in testing (p=0.001).

CONCLUSIONS

The findings support the need to assess barriers and facilitators to testing decisions in order to increase testing rates. In particular, AIDS knowledge and either problem or emotional-focused coping and risky behaviors, based on gender may be important in making testing and care entry decisions.

Current diagnostic methods for HIV

Detection of HIV infection is essential for diagnosis and monitoring of the infection. There are different types of diagnostic tools available that are based on detection of HIV-specific antibodies, viral antigen or nucleic acid. Sensitivities and specificities of assays utilized for HIV detection have improved. Newer HIV testing technologies such as third-generation enzyme immunoassay which detect HIV-specific IgG and IgM antibodies, fourth-generation enzyme immunoassay which detect both anti-HIV antibodies and HIV p24 antigen and nucleic acid based tests for HIV RNA have significantly decreased the window period. This review provides an overview of current technologies for the detection and monitoring of HIV infection and recent advances in the field of HIV diagnosis.

Rapid diagnosis in serology

Serological diagnosis of acute phase infections implies the detection of IgM specific response, an effective marker of primary infection, but with less clinical significance in reactivations or reinfections. The aim of this article is to provide an updated view of the rapid diagnosis in serology by detecting the IgM isotype and reviewing its applications and limitations. Point-of-care (PoC) tests are analyzed. PoC tests are used in geographical areas where traditional tests are not available, as well as in other circumstances where their use brings the diagnosis directly to the target population. Likewise, their use reduces the response time between taking the sample and the diagnosis, making it easier to make clinical decisions. PoC assays have proven cost-effective, especially in preventing vertical transmission of syphilis and HIV infection.