Search

Background: HIV screening (i.e. antigen/antibody) tests are followed by a supplemental (i.e. antibody-only) if the screen is positive. Discrepant results can result from two scenarios: a false-positive screening test or acute HIV infection. These scenarios can be distinguished by a molecular HIV test, but due to contamination concerns, our laboratory recently implemented a policy requiring a second specimen dedicated for molecular HIV testing. Our objective was to (1) characterize the effect of this policy on the time-to-diagnosis for patients with discrepant screening and supplemental test results, and (2) explore "strength of positivity" as an interim predictor of screening test accuracy while awaiting confirmatory test results., Methods: Data from our laboratory information system, electronic health record, and instrument logs were used to collate data for all HIV testing performed at Barnes-Jewish Hospital (BJH) between January 1, 2014 and October 18, 2017., Results: Requiring a dedicated specimen for molecular testing significantly increased the time-to-diagnosis for patients with discrepant screening and supplemental HIV tests (p = 0.0084). This policy also contributed to loss-to-followup, with 0/35 discrepant cases lost-to-followup prior to policy implementation compared to 2/10 after implementation. However, by optimizing the signal-to-cutoff (S/CO) ratio of the screening test, we were able to more accurately distinguish false-positives from acute-HIV prior to molecular testing (sensitivity of 100%, specificity of 89%)., Conclusions: We propose utilizing quantitative fourth-generation assay results (S/CO) ratios as a predictor of infection true positivity in situations where the screening assay is reactive but the supplemental test is negative and confirmatory molecular results are not immediately available., Competing Interests: The authors have declared that no competing interests exist.

Rapid HIV testing may circumvent the practical barriers to HIV testing in several settings. User preference of the testing kits available has been relatively underexplored. We examined healthcare provider (HCP) ratings of two validated rapid testing kits in clinical practice. From 1 July to 1 December 2012 we prospectively recruited HCPs (clinic nurses) from three outpatient clinics linked to Lausanne University Hospital, Lausanne, Switzerland. The HCPs had experience in taking blood samples but varying experience in rapid HIV testing. Participating HCPs performed rapid HIV testing using Determine™ Combo (DETE) or INSTI™ (INSTI), according to a predefined randomization sequence, and rated practical aspects of each test using a Likert scale. Seventeen HCPs of 23 approached (74%) were eligible and agreed to participate, performing a total of 336 HIV tests. Globally, the testing procedure was rated as easy or very easy by 97% (DETE) to 99% (INSTI) of tests performed. Among experienced HCPs, DETE was rated easier than INSTI for kit storage (p < 0.001) and blood collection ( P = 0.012) while INSTI was rated easier than DETE for blood application ( P = 0.001) and test interpretation ( P = 0.005). Among less experienced HCPs, both tests performed equally with the exception of test interpretation ( P < 0.001) and overall ease of use ( P = 0.05) in favour of INSTI. Of all HCPs, 94% stated they would recommend INSTI over DETE based on the time to result, ease of test interpretation and overall ease of use. Rapid HIV testing was considered easy to perform, even by inexperienced nursing staff. Whilst both tests were considered easy to use, the HCPs in this study preferred INSTI to DETE overall, due to rapid time to result, ease of test interpretation and general ease of use.

Background and Objective: The rapid test study was a real-time comparison of point-of-care (POC) HIV tests to determine their abilities to detect early HIV infection., Study Design: Men and transgender persons reporting sex with men in the prior year were recruited at the Public Health-Seattle & King County STD Clinic, Gay City Health Project, and University of Washington Primary Infection Clinic. Study tests included the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test performed on oral fluids and tests performed on fingerstick whole blood specimens including OraQuick, Uni-Gold Recombigen HIV test, Determine HIV-1/2 Ag/Ab Combo, and INSTI HIV-1 Rapid Antibody Test. Specimens from subjects with negative results were sent for EIA and nucleic acid amplification testing. McNemar's exact tests compared the numbers of HIV-infected subjects detected., Results: Between February 2010 and August 2014, there were 3438 study visits. Twenty-four subjects had discordant POC results with at least one reactive and one non-reactive test, including one subject with a reactive Determine p24 antigen. OraQuick performed on oral fluids identified fewer persons compared to all fingerstick tests. OraQuick performed on fingerstick whole blood detected fewer persons compared to the Determine Combo antibody component (p=.008) and Combo overall (p=.004), and there was a trend when compared to INSTI (p=.06). The Determine Combo specificity was 98.99%., Conclusions: As reported by others, Determine Combo underperforms compared to laboratory-based testing, but it did detect one acute infection. If these results are validated, the specificity of Determine Combo may limit its usefulness in populations with lower HIV incidence., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Objectives: UK guidelines recommend routine HIV testing in general clinical settings when the local HIV prevalence is > 0.2%. During pilot programmes evaluating the guidelines, we used laboratory-based testing of oral fluid from patients accepting tests. Samples (n = 3721) were tested manually using the Bio-Rad Genscreen Ultra HIV Ag-Ab test (Bio-Rad Laboratories Ltd, Hemel Hempstead, UK). This was a methodologically robust method, but handling of samples was labour intensive. We performed a validation study to ascertain whether automation of oral fluid HIV testing using the fourth-generation HIV test on the Abbott Architect (Abbott Diagnostics, Maidenhead, UK) platform was possible., Methods: Oral fluid was collected from 143 patients (56 known HIV-positive volunteers and 87 others having contemporaneous HIV serological tests) using the Oracol+ device (Malvern Medicals, Worcester, UK). Samples were tested concurrently: manually using the Genscreen Ultra test and automatically on the Abbott Architect., Results: For oral fluid, the level of agreement of results between the platforms was 100%. All results agreed with HIV serology. The use of the Oracol+ device produced high-quality samples. Subsequent field use of the test has shown a specificity of 99.97% after nearly 3000 tests., Conclusions: Laboratory-based HIV testing of oral fluid requires less training of local staff, with fewer demands on clinical time and space than near-patient testing. It is acceptable to patients. The validation exercise and subsequent clinical experience support automation, with test performance preserved. Automation reduces laboratory workload and speeds up the release of results. Automated oral fluid testing is thus a viable option for large-scale HIV screening programmes., (© 2013 British HIV Association.)

Since the introduction in the mid-1980s, HIV testing has gradually improved both in terms of sensitivity and specificity. The so-called fourth generation of tests, combined HIV antigen/antibody assays, has now been introduced. This study compares three automated combined assays with older third-generation antibody assays in large-scale screening. Serum samples from routine screening of blood and plasma donors and clinical samples were investigated for specificity evaluation. Three fourth-generation combination assays from one manufacturer were compared with three older third-generation antibody assays from the same manufacturer. More than 40 000 samples per assay were included. For sensitivity, selected panels of confirmed HIV-1- and HIV-2-positive samples as well as seroconversion samples (HIV-1) from commercial panels and also from patients who appeared during the evaluation were used. The specificities of the fourth-generation tests were 99.91% (AxSYM), 99.95% (ARCHITECT) and 99.97% (PRISM) after repeated testing. Some specificity variation between reagent batches was observed. All HIV-1-positive samples were reactive by the three fourth-generation systems. HIV-1 seroconversion samples and panels were reactive earlier than by antibody-only tests. As for HIV-2 samples, AxSYM failed to detect one (n = 40), whereas PRISM and ARCHITECT detected all (n = 16 for PRISM and n = 52 for ARCHITECT). The new HIV antigen/antibody combination assay systems were found to have high sensitivity and specificity. The instruments provided a rational and easy way of testing at large scale.

The first HIV-1 marker that appears in blood following infection is HIV-1 RNA and usually the load is in millions of copies/ ml preceding seroconversion. A 24-year-old pregnant woman, gravida 2, parity 1 was tested for HIV as part of antenatal screening. Three samples were collected and tested from this individual over a period 70 days. The HIV-1 RNA level during seroconversion phase was very low, contrary to the well understood natural history of HIV infection. The reactivity rate in the ELISA and the Western Blot profile showed a gradual increase over the 70 days with a weak reactivity in a second generation assay (detects IgG only) for the third sample. This case illustrates the uncertainties regarding the serological window period in HIV infection and the need to use at least a third generation assay in testing centres for early detection of HIV infection.

Background: The objectives of the present study were: to determine the sensitivity and specificity of oral fluid testing compared with the performance of standard blood-based HIV enzyme immunoassay; to assess the feasibility of oral fluid specimen collection from clients for the purposes of HIV testing within a clinical setting; and to assess the clinical and laboratory impact regarding staffing, material resources, expertise and funding of oral fluid testing., Methods: A parallel comparative trial of oral fluid and blood testing was conducted among a group of HIV positive clients and a group of unknown HIV serostatus clients where each client was offered both tests. An ambulatory HIV clinic recruited 175 known HIV positive clients and 179 persons were recruited through an inner city sexual health clinic while attending for routine sexual health checks. Client responses to oral fluid collection were assessed. The sensitivity and specificity of oral fluid testing were calculated., Results: Of the 176 confirmed HIV reactive blood test results, the OraSure (OraSure Technologies, Beaverton, OR, USA) assay failed to detect only one of these, demonstrating a sensitivity of 99.4%. Of the 178 blood specimens that were tested as non-reactive by the AxSYM (Abbott Laboratories, Abbott Park, IL, USA) Combo system, OraSure recorded four of the corresponding oral fluid specimens as reactive (assumed to be false-positive), giving a specificity of 97.6%. Although evaluation of patients undergoing the test showed a large proportion (88.6%) preferred the OraSure test to conventional blood testing, a large minority of these (22.6%) made such a preference conditional on the OraSure test being as reliable as current blood testing., Conclusions: This limited clinic based trial of oral fluid testing for HIV antibodies among an outpatient population has demonstrated the potential of oral fluid as a specimen for HIV testing. However, the lower performance of the test compared with current serum-based tests may limit the usefulness of OraSure to epidemiological studies or as an alternative screening tool in outreach settings among higher risk populations.

This study aimed to provide evaluation information about rapid HIV kits by the anti-HIV External Quality Assessment Schemes (EQAS) panel of the Korea National Institute of Health (KNIH) and the rapid HIV test panel of the US Centers for Disease Control and Prevention (CDC). Each KNIH anti-HIV EQAS panel from 2003 to 2005 consisted of four or five samples of plasma obtained from blood donors with a strong positive or negative reaction to HIV. KNIH delivered each panel to public health centers for analysis of the HIV test results, and the reactivity of the five rapid HIV kits currently used in the Korean market were compared with that of a CDC reference. The analytic sensitivity and specificity of the rapid HIV kits for the KNIH anti-HIV EQAS in 2005 were 99.3 and 99.1%, respectively; in 2004, 98.8 and 97.1%; and in 2003, 94.8 and 95.9%. Five HIV kits from the CDC panel consistently showed positive reactivity for strong positive samples in all kits, but some showed erratic reactivity for weakly positive samples. This is the first report on post-evaluation of rapid HIV kits in the Korean market by an anti-HIV EQAS panel. It was found that the quality of performance of the rapid HIV tests had improved each year but should be interpreted with caution for weakly positive samples.

Quality assurance of HIV testing is essential to correctly assess the HIV epidemic. To describe the characteristics of HIV testing and identify features that could be improved, a questionnaire on the quality of HIV tests was sent to Catalan laboratories in 1998. The survey revealed variability in the procedures used by the participating laboratories when performing HIV tests. Some of the laboratories were still performing incorrect activities such as identifying HIV specimens with specific labels, extracting new specimens for a second test to confirm diagnosis, or failing to guarantee the confidentiality of the results. The criteria for HIV testing should be standardized according to the purpose of the test and the prevalence of the infection in the population analyzed. This approach would improve the quality of the results of diagnostic tests, since the overall concept of quality includes the entire process (pre-test, test and post-test).

Background: The purpose of this study was to estimate the risk of human immunodeficiency virus (HIV) infection via the transfusion of blood tested by inappropriately stored or expired rapid antibody assays in Zambia., Study Design and Methods: Surgical patients (n = 370) were tested with antibody assays (HIV-spot and HIV 1+2) that had expired 3 to 6 months previously. Blood donors (n = 211) were tested by inappropriately stored but non-expired HIV-spot assay. Serum samples from both groups were retested with enzyme immunoassays, and the seropositivity of samples was confirmed by immunoblotting., Results: Seroprevalence in surgical patients and blood donors was 19.8 and 11.6 percent, respectively. Sensitivity and specificity of HIV-spot (expired) were 88.2 and 98.1 percent; those of HIV 1+2 (expired) were 82.1 and 94.7 percent; and those of HIV-spot (non-expired) were 91.7 and 98.8 percent, respectively. The risk of HIV infection via the transfusion of blood tested by HIV-spot (expired), HIV-spot (nonexpired), or HIV 1+2 (expired) was calculated to be 1.4, 1.0, and 3.2 percent, respectively., Conclusion: Manufacturers of the HIV-spot and HIV 1+2 assays claim sensitivity and specificity of 98.8 and 100 percent and 100 and 99.5 percent, respectively. In this study, sensitivity and specificity were 11 to 18 percent lower. Moreover, in-date reagents also performed less well than the manufacturers claimed, but the worst results were with expired or improperly stored reagents. According to the manufacturers of HIV-spot and HIV 1+2, the risk of HIV infection would be 0.2 and 0 percent, respectively. However, the risk of contracting HIV through transfusion is at least six times higher than expected.

Objectives: To determine the sensitivity of HIV-antibody assays for detecting low levels of HIV antibody using seroconversion and other panels containing plasma of varying titres., Methods: Eight HIV-antibody assays, available under the World Health Organization bulk-procurement agreement, were evaluated on sets of sequential plasma samples derived from 11 individuals who had recently become HIV-infected (seroconversion panels). In addition, two non-seroconversion panels, consisting of low performance (titre) and mixed titre samples were used to further define the sensitivity of the assays. The eight assays included two rapid tests, one simple test, and five enzyme-linked immunosorbent assays (ELISA)., Results: On average, the eight assays detected antibody 0.5-4.8 days later than the reference test (Abbott HIV-1/HIV-2 3rd generation ELISA); these differences were statistically significant for six of the eight tests. All tests performed well on the low performance and mixed titre panels. All eight assays also had comparable sensitivity to that of the reference test on a large panel of known positive plasma. The additional risk of missing an infectious unit of blood during seroconversion by using the least sensitive rather than the reference test was estimated to be 1 in 7600 and 1 in 76 million at annual HIV incidence rates of 1 and 0.0001%, respectively. The cost of eliminating this additional risk by using the reference test is between US$ 15,150 and 151 million per unit detected at the above incidence rates., Conclusions: Although there are differences in sensitivity between the assays when used to test blood from individuals during the course of seroconversion, the differences are small, and all eight tests are appropriate for use as screening tests.

In response to recent laws regulating human immunodeficiency virus (HIV) antibody testing practices in all federal hospitals, our university-affiliated Veterans Affairs Hospital instituted several interventions designed to increase appropriate testing. Specific hospital policy requiring restriction of testing to high-risk individuals, provision of pre- and posttest counseling, and documentation of written consent was instituted. In addition, an education campaign to inform physicians of hospital policy and training of counselors as physician extenders was undertaken. To determine the efficacy of these interventions, we reviewed all HIV antibody tests performed during a subsequent six-month period (n = 221). Only 14% of tests met all hospital policy requirements. The decision to test was prompted by identification of a risk factor or other acceptable reason for testing for only 31% of patients. Risk reduction counseling was provided for only 28% of patients. Written consent was documented for 62% of patients. Health care providers on surgical services were less likely than others to comply with hospital policy (p < 0.0001). We conclude that an interventional program including specific hospital policy mandates, physician education, and provision of trained counselors was not adequate to ensure optimal HIV antibody testing practices. If this gap between policy and practice is to be closed, additional interventions, or alternatively modification of policy guidelines, will be needed.

Testing for HIV and such issues as test accuracy, informed consent, reporting requirements, and confidentiality related to testing are reviewed. Pre-test and posttest counseling is discussed, and a sample form to guide family physicians in obtaining informed consent is provided.

In a population-based national survey conducted in 1988-90, more than one million neonatal dried-blood specimens were tested for maternal antibody to human immunodeficiency virus type 1 (HIV-1). Enzyme immunoassays (EIA) and Western blot tests were performed in 20 state laboratories following standardized procedures. The observed predictive value of a repeatedly reactive EIA results closely coincided with that expected on the basis of manufacturer's estimates of test sensitivity and specificity for dried-blood specimens. Of the 2,845 EIA-reactive specimens tested by Western blot, 1,323 (47%) were positive, 1,270 (45%) were negative, and 252 (9%) were indeterminate. False-positive EIA and indeterminate Western blot results occurred at rates independent of seroprevalence. These data help characterize the results to be expected from screening of similar low-seroprevalence populations and constitute a base line for the detection of systematic testing errors.

In May 1988, the Centers for Disease Control's Model Performance Evaluation Program (Atlanta, Ga) surveyed 1092 laboratories that performed enzyme immunoassays and Western blot tests for human immunodeficiency virus type 1 antibody on mailed plasma samples of known human immunodeficiency virus type 1 antibody reactivity and that described their laboratory characteristics and testing practices. The study objective was to evaluate the quality of laboratory performance in testing for human immunodeficiency virus type 1 antibody. After identifying relevant variables in univariate analyses, multivariate analyses were performed using stepwise logistic models. Human immunodeficiency virus type 1 antibody test performance was independently associated with analytic variables such as commercial test kit used and with nonanalytic variables such as experience, training, and degree requirements of laboratory personnel. These results validate the importance of nonanalytic variables to the quality of outcomes in laboratory testing.

Participation in external quality assessment (EQA) has been mandatory in France as from 1978. The Ministry of Health has responsibility for maintenance of a list of laboratories and contracts EQA schemes to be organised and supervised by scientific groups. Serological markers for viral hepatitis B and anti-HIV were included in surveys, four times per annum, as from 1985. The number of laboratories participating increased from 178 for anti-HIV and 499 for viral hepatitis markers in 1985 to 3421 for anti-HIV and 2384 for viral hepatitis markers at the present time. The percentage of correct results varies depending on the method and specimen from 98% to 99% for anti-HIV and from 95% to 97% for HBsAg; the false negative rate has been as high as 14% for anti-HBs.

Since december 1st 1988, the Retrovirus study Group of the French Society of Blood Transfusion has initiated a systematic multicentric control of all anti-HIV screening EIA test kits lots used by each member of the group. For this purpose a special panel (GRV) has been designed and forwarded to each laboratory. From december 1st 1988 to august 8 1989, 6 HIV-1 kits have been in use (Diagnostics Pasteur Elavia 1; Diagnostics Pasteur Rapid'Elavia; Organon Vironostika; Abbott HIV recombinant; Du Pont env 9; Wellcome Wellcozyme). The GRV panel has been run 204 times on 102 different lots in 12 laboratories. Results after 9 months show that these 6 kits almost always properly recognize the 5 HIV 1 positive samples of the panel. However they differ in their ability to recognize HIV 2 positive samples. Variations in results are observed from lot to lot as well as between the first half of this period and the second.

In order to evaluate the effect of heat inactivation on serum undergoing testing for HIV antibody, 100 heat-inactivated and nonheat-inactivated serum samples were tested by two modifications of Abbott's screening assays for human T-cell lymphotropic virus type-III (lot numbers 1037 and 3036) and by two confirmatory assays (Cambridge BioScience CBre3-EIA; Damon Corporation Western blot). The samples consisted of 75 HIV antibody-negative and 25 HIV antibody-positive sera. The specimens were divided into two equal aliquots. One set was not subjected to heat inactivation, while the others were subjected to heat inactivation at 56 degrees C for 30 min. Heat inactivation had no significant effect on the HIV-position sera; however, heat-inactivated, negative sera evaluated by Abbott lot numbers 1037 and 3036 resulted in false-positive rates of 8% and 7%, respectively. No false positives were generated by the two confirmatory assays; however, the CBre3-EIA recombinant envelope protein assay had a significantly increased optical density reading following heat inactivation of the negative sera. The Western blot procedure used in the study was not affected by heat inactivation.