Human Immunodeficiency Virus Nucleic Acid Research Articles

LSPR aptasensor based on gold nanoparticles for rapid detection of HIV type-1 nucleic acid

Introduction: Economic and dependable detection of the human immunodeficiency virus (HIV) is crucial to controlling and managing the infection, especially for almost half of the HIV-affected population (46%) unaware of their HIV status. Currently, the existing technologies’ cost, expertise, and time requirements severely restrict their widespread use, particularly among populations with limited resources. Objectives: The current study aimed to design a rapid and low-cost assay platform to detect qualitatively and quantitatively the unamplified HIV RNA using gold nanoparticles’ (AuNPs’) unique physicochemical and optical properties. This research is based on inducing the aggregation of AuNPs functionalized with a thiol-modified probe by a cationic agent. Patients and Methods: In this experimental study, total RNA was extracted from 56 patients with established HIV infection and 38 healthy HIV-negative participants, followed by mixing the extracted RNA, AuNP-probes, and cationic-AuNPs. Next, the solutions’ color changes were assessed visually and by UV-vis spectrophotometry. The viral load of each sample was calculated using the equation established by the standard curve. Results: The assay could detect HIV-RNA extracted from plasma, and the results were comparable to those of reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Target-AuNP-probe hybrids were stable during aggregation after adding the cationic inducer. The standard curve plot showed a relatively wide linear range. With 89.2% sensitivity and 92.1% specificity, the test had a limit of detection (LOD) of 160 IU/mL. Conclusion: To our knowledge, this is the first study on the effect of using modified gold and cationic nanoparticles to detect non-amplified HIV nucleic acid. The assay detected HIV-RNA within 70 minutes, confirmed by color changes visible to the naked eye and measurable by recording the absorption spectrum. This technology can be extended to identify other nucleic acid targets and adapt full automation.

Assessing donor suitability for blood donation: Utility of Geenius HIV 1/2 confirmatory assay

BackgroundBlood donor care and blood safety require a quick and accurate decision on the presence or absence of Human Immunodeficiency Virus (HIV) infection, based on the proper selection of blood donors, serological and molecular HIV testing as well as western blot test. The aim was investigating the possibility of inclusion of Geenius HIV 1/2 Confirmatory Assay in blood donor testing algorithm in order to shorten test time and decrease the number of indeterminate results. MethodsA total of 75 archived serum/plasma samples were tested. Their previous serological and molecular HIV results were: 3 negative samples, 7 positive samples, 65 serological indeterminate or positive but confirmatory testing and NAT negative samples. ResultsGeenius assay confirmed the presence of antibodies in all blood donors with HIV positive serology and Nucleic Acid Testing (NAT). HIV-1 gp160 and gp41 antibodies were detected in these donors, while p31 and p24 antibodies were not detected in two and three donors, respectively. HIV-2 antibodies gp36 and gp140 were not found. Blood donor with HIV indeterminate or positive serology but negative confirmatory testing and NAT, were negative in Geenius assay.Conclusion The results obtained are consistent with western blot results. The assay proved simple and quick to perform. Studies have confirmed the possibility of introducing Bio-Rad Geenius into a routine blood donor testing protocol.

Assessing Solid Organ Donors and Monitoring Transplant Recipients for Human Immunodeficiency Virus, Hepatitis B Virus, and Hepatitis C Virus Infection - U.S. Public Health Service Guideline, 2020.

SummaryThe recommendations in this report supersede the U.S Public Health Service (PHS) guideline recommendations for reducing transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) through organ transplantation (Seem DL, Lee I, Umscheid CA, Kuehnert MJ. PHS guideline for reducing human immunodeficiency virus, hepatitis B virus, and hepatitis C virus transmission through organ transplantation. Public Health Rep 2013;128:247–343), hereafter referred to as the 2013 PHS guideline. PHS evaluated and revised the 2013 PHS guideline because of several advances in solid organ transplantation, including universal implementation of nucleic acid testing of solid organ donors for HIV, HBV, and HCV; improved understanding of risk factors for undetected organ donor infection with these viruses; and the availability of highly effective treatments for infection with these viruses. PHS solicited feedback from its relevant agencies, subject-matter experts, additional stakeholders, and the public to develop revised guideline recommendations for identification of risk factors for these infections among solid organ donors, implementation of laboratory screening of solid organ donors, and monitoring of solid organ transplant recipients. Recommendations that have changed since the 2013 PHS guideline include updated criteria for identifying donors at risk for undetected donor HIV, HBV, or HCV infection; the removal of any specific term to characterize donors with HIV, HBV, or HCV infection risk factors; universal organ donor HIV, HBV, and HCV nucleic acid testing; and universal posttransplant monitoring of transplant recipients for HIV, HBV, and HCV infections. The recommendations are to be used by organ procurement organization and transplant programs and are intended to apply only to solid organ donors and recipients and not to donors or recipients of other medical products of human origin (e.g., blood products, tissues, corneas, and breast milk). The recommendations pertain to transplantation of solid organs procured from donors without laboratory evidence of HIV, HBV, or HCV infection. Additional considerations when transplanting solid organs procured from donors with laboratory evidence of HCV infection are included but are not required to be incorporated into Organ Procurement and Transplantation Network policy. Transplant centers that transplant organs from HCV-positive donors should develop protocols for obtaining informed consent, testing and treating recipients for HCV, ensuring reimbursement, and reporting new infections to public health authorities.

Three Years of Shared Service HIV Nucleic Acid Testing for Public Health Laboratories: Worthwhile for HIV-1 but Not for HIV-2.

In 2016, HIV-2 nucleic acid testing (NAT) was added to a shared service program that conducts HIV-1 NAT for public health laboratories performing the recommended algorithm for diagnosing HIV. Here, we evaluate the usefulness of HIV-2 NAT in this program as compared with HIV-1 NAT. Specimens eligible for HIV-1 NAT were reactive on an HIV-1/2 antibody or antigen/antibody initial test and nonreactive or indeterminate on a supplemental antibody test or were reactive for HIV-1 antigen-only on an HIV-1/2 antigen/antibody initial test. Specimens eligible for HIV-2 NAT were reactive on an initial test, HIV-2 indeterminate or HIV indeterminate on a supplemental antibody test and had no detectable HIV-1 RNA or were reactive for HIV-2 antibody on an HIV-1/2 antigen/antibody test, and this reactivity was not confirmed with a supplemental antibody assay. All specimens were tested in a reference laboratory using APTIMA HIV-1 qualitative RNA and/or a validated qualitative HIV-2 RNA real-time PCR assay. During 2016 to 2019, HIV-1 RNA was detected in 234 (14%) of 1731 specimens tested. HIV-2 RNA was not detected in 52 specimens tested. Median time from specimen collection to reporting of HIV-1 and HIV-2 NAT results by year ranged from 9 to 10 days and from 22 to 27 days, respectively. Two specimens with HIV-2 indeterminate results on a supplemental antibody test had detectable HIV-1 RNA. A shared service model for HIV-1 NAT is both feasible and beneficial for public health laboratories. However, because no HIV-2 infections were detected, our data suggest that this program should reconsider the usefulness of HIV-2 NAT testing.

Sensitivity enhancement of lateral flow assay by embedding cotton threads in paper

Lateral flow assays (LFAs) have been extensively used as point-of-care testing platforms because they are inexpensive, portable, simple, and rapid, which particularly improve their availability in resource-poor settings. However, the poor sensitivity of LFAs restricts their further applications. Herein, we proposed a novel and simple method to enhance the detection sensitivity of LFAs by embedding cotton thread-based barriers into paper and further integrating them into strips to decrease the flow rate of sample and extend the reaction time. The number and hydrophilicity of the embedded cotton threads were sequentially optimized. The flow rate of liquid in cotton thread-embedded LFAs was mathematically simulated using a circuit-like model and the simulation results are consistent with the experimental results. With using human immunodeficiency virus nucleic acid as a model target, the cotton thread-embedded LFAs presented a fourfold enhancement in detection sensitivity compared to that of the unmodified LFAs. The strategy of embedding cotton threads into paper possesses great potential for fabricating other paper-based microfluidic devices in the future.

A Simple Symptom Score for Acute Human Immunodeficiency Virus Infection in a San Diego Community-Based Screening Program

Treatment of acute human immunodeficiency virus (HIV) infection (AHI) decreases transmission and preserves immune function, but AHI diagnosis remains resource intensive. Risk-based scores predictive for AHI have been described for high-risk groups; however, symptom-based scores could be more generalizable across populations. Adults who tested either positive for AHI (antibody-negative, HIV nucleic acid test [NAT] positive) or HIV NAT negative with the community-based San Diego Early Test HIV screening program were retrospectively randomized 2:1 into a derivation and validation set. In the former, symptoms significant for AHI in a multivariate logistic regression model were assigned a score value (the odds ratio [OR] rounded to the nearest integer). The score was assessed in the validation set using receiver operating characteristics and areas under the curve (AUC). An optimal cutoff score was found using the Youden index. Of 998 participants (including 261 non-men who have sex with men [MSM]), 113 had AHI (including 4 non-MSM). Compared to HIV-negative cases, AHI cases reported more symptoms (median, 4 vs 0; P < .01). Fever, myalgia, and weight loss were significantly associated with AHI in the multivariate model and corresponded to 11, 8, and 4 score points, respectively. The summed score yielded an AUC of 0.85 (95% confidence interval [CI], .77-.93). A score of ≥11 was 72% sensitive and 96% specific (diagnostic OR, 70.27). A 3-symptom score accurately predicted AHI in a community-based screening program and may inform allocation of resources in settings that do not routinely screen for AHI.

Costs per Diagnosis of Acute HIV Infection in Community-based Screening Strategies: A Comparative Analysis of Four Screening Algorithms.

In nonhealthcare settings, widespread screening for acute human immunodeficiency virus (HIV) infection (AHI) is limited by cost and decision algorithms to better prioritize use of resources. Comparative cost analyses for available strategies are lacking. To determine cost-effectiveness of community-based testing strategies, we evaluated annual costs of 3 algorithms that detect AHI based on HIV nucleic acid amplification testing (EarlyTest algorithm) or on HIV p24 antigen (Ag) detection via Architect (Architect algorithm) or Determine (Determine algorithm) as well as 1 algorithm that relies on HIV antibody testing alone (Antibody algorithm). The cost model used data on men who have sex with men (MSM) undergoing community-based AHI screening in San Diego, California. Incremental cost-effectiveness ratios (ICERs) per diagnosis of AHI were calculated for programs with HIV prevalence rates between 0.1% and 2.9%. Among MSM in San Diego, EarlyTest was cost-savings (ie, ICERs per AHI diagnosis less than $13.000) when compared with the 3 other algorithms. Cost analyses relative to regional HIV prevalence showed that EarlyTest was cost-effective (ie, ICERs less than $69.547) for similar populations of MSM with an HIV prevalence rate >0.4%; Architect was the second best alternative for HIV prevalence rates >0.6%. Identification of AHI by the dual EarlyTest screening algorithm is likely to be cost-effective not only among at-risk MSM in San Diego but also among similar populations of MSM with HIV prevalence rates >0.4%.

Can HIV Be Cured and Should We Try?

An estimated 35.0 million persons live with HIV; 2.1 million new infections occurred and 1.5 million persons died of HIV in 2013 (World Health Organization, http://www.who.int/hiv/data/epi_core_dec2014.png?ua=1). Despite effective combination antiretroviral therapy (cART), less than one-quarter of patients can access these life-prolonging medications; and despite its effectiveness, cART does not normalize life expectancy, as premature aging, metabolic complications and chronic inflammation complicate HIV therapy. HIV is incurable due to the presence of a latent viral reservoir. During the life cycle of the virus, HIV integrates into the host DNA. A subset of integrated HIV provirus remains transcriptionally silent, producing neither viral proteins nor viral progeny, until reactivation by various physiologic stimuli. This latency of HIV allows some infected cells to escape immune detection and elimination, and these latently infected cells constitute the viral reservoir. The latent viral reservoir allows viral rebound within weeks of interruption of cART, 1,2 where the magnitude of viral replication approaches that present pre-therapy. Although it was once thought that viral rebound occurred universally following therapy interruption, several recent reports challenge that paradigm. The “Berlin patient” successfully cleared HIV after two allogeneic transplants from a donor with homozygous CCR5Δ32 mutation,3 and he has not rebounded HIV after nearly seven years. This case likely represents a cure from HIV; yet other cases have been described where HIV rebound has been attenuated, or delayed. The “Mississippi” baby was a perinatally HIV-infected infant who initiated cART within hours of birth, and when interrupted eighteen months later, viremia remained undetectable for nearly two years.4 The Harvard BMT cases underwent allogeneic BMT, developed undetectable HIV DNA, yet rebounded viremia within only eight months after cART discontinuation.5 Together these cases demonstrate that control of viremia in the absence of cART is possible, if not durable.4 The VISCONTI cohort of 14 HIV-infected adults who initiated antiretroviral therapy during acute infection, and in whom high level rebound viremia had not occurred several years after cessation of therapy,6 similarly demonstrated that viral rebound following cART interruption can be attenuated. These cases have reinvigorated research toward finding a cure for HIV, which certainly will require an exceptional investment of time, talent and resources. Thus it is prudent to question whether such resources would be better devoted to more proximate needs with proven results (such as supplying cART to those without access to it, or supplying pre/post exposure prophylaxis to reduce the rate of new infections).

DNA damage repair machinery and HIV escape from innate immune sensing.

Viruses have been long known to perturb cell cycle regulators and key players of the DNA damage response to benefit their life cycles. In the case of the human immunodeficiency virus (HIV), the viral auxiliary protein Vpr activates the structure-specific endonuclease SLX4 complex to promote escape from innate immune sensing and, as a side effect, induces replication stress in cycling cells and subsequent cell cycle arrest at the G2/M transition. This novel pathway subverted by HIV to prevent accumulation of viral reverse transcription by-products adds up to facilitating effects of major cellular exonucleases that degrade pathological DNA species. Within this review we discuss the impact of this finding on our understanding of the interplay between HIV replication and nucleic acid metabolism and its implications for cancer-related chronic inflammation.

HIV Infection in Gastric Epithelial Cells

Many chronic human immunodeficiency virus (HIV) patients suffer from gastric complaints, including gastric tuberculosis and coinfection of other pathogens. Recent work has demonstrated that a variety of nonimmune cells can act as viral reservoirs, even at the early stage of HIV infection. In this study, we detect HIV viral particles, proteins, and nucleic acids in gastric epithelial cells using clinical samples. These observations are further supported by a simian immunodeficiency virus-infected macaque model. Further, the number of HIV-infected gastric epithelial cells is positively associated with blood viral load, and is negatively correlated with CD4 lymphocyte cell counts. We also demonstrate that HIV infection is accompanied by severe inflammatory response in gastric mucosa. Additionally, HIV infection activates signal transducer and activator of transcription 3 and RelA, and enhances the production of interleukin 6 and tumor necrosis factor α in gastric epithelial cells. The present data suggest that the gastric epithelial cells are natural targets of HIV infection, and HIV infection in epithelial cells contributes to HIV-induced gastric mucosal inflammation.

Detection of infections with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus by analyses of dried blood spots - performance characteristics of the ARCHITECT system and two commercial assays for nucleic acid amplification

BackgroundNowadays, dried blood spots (DBS) are primarily used to obtain diagnostic access to risk collectives such as intravenous drug users, who are prone to infections with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Before DBS analyses can be used in this diagnostic context, however, a comprehensive evaluation of its performance characteristics must be conducted. To the best of our knowledge, the current study presents for the first time such essential data for the Abbott ARCHITECT system, which is currently the worldwide leading platform in this field of infection diagnostics.MethodsThe investigation comprised 1,762 paired serum/DBS samples and a total of 3,524 determinations with the Abbott ARCHITECT HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24-antigen/anti-HIV 1/2 assays as well as with the artus HBV LC PCR and VERSANT HCV RNA qualitative (TMA) tests.ResultsIn the context of DBS testing, a specificity of 100% was recorded for the seven serological and molecular biological assays. The analytical sensitivity of HBsAg, anti-HBc, anti-HBs, anti-HCV, HIV-1-p24-antigen/anti-HIV 1/2, HBV DNA, and HCV RNA detections in DBS eluates was 98.6%, 97.1%, 97.5%, 97.8%, 100%, 93%, and 100%, respectively.Discussion/conclusionsThe results obtained indicate that it is today possible to reliably detect HBsAg, anti-HBc, anti-HBs, anti-HCV and HIV-1-p24 antigen/anti-HIV 1/2 with state-of-the-art analytical systems such as the Abbott ARCHITECT in DBS eluates even when a comparatively high elution volume of 1,000 μl is used. They also provide evidence for the inherent analytical limits of DBS testing, which primarily concern the anti-HBc/anti-HBs system for individuals with HIV infections and nucleic acid tests with relatively low analytical sensitivity.

HIV Screening Practices for Living Organ Donors, New York State, 2010: Need for Standard Policies

Our survey of kidney and liver transplant centers in New York State found a wide variation among transplant centers in evaluation and screening for HIV risk and infection among prospective living donors. Survey results underscore the need to standardize practices. A recent transmission of human immunodeficiency virus (HIV) from a living donor to a kidney recipient revealed a possible limitation in existing screening protocols for HIV infection in living donors. We surveyed kidney and liver transplant centers (N=18) in New York State to assess HIV screening protocols for living donors. Although most transplant centers evaluated HIV risk behaviors in living donors, evaluation practices varied widely, as did the extent of HIV testing and prevention counseling. All centers screened living donors for serologic evidence of HIV infection, either during initial evaluation or ≥1 month before surgery; however, only 50% of transplant centers repeated HIV testing within 14 days before surgery for all donors or donors with specific risk behaviors. Forty-four percent of transplant centers used HIV nucleic acid testing (NAT) to screen either all donors or donors with recognized risk behaviors, and 55% never performed HIV NAT. Results suggest the need to standardize evaluation of HIV risk behaviors and prevention counseling in New York State to prevent acquisition of HIV by prospective living organ donors, and to conduct HIV antibody testing and NAT as close to the time of donation as possible to prevent HIV transmission to recipients.

Detection and management of acute HIV infections in patients with sexually transmitted infections: a window of opportunity for HIV prevention within South Africa?

Patients with acute human immunodeficiency virus (HIV) infection are highly infectious to their uninfected sexual partners. The level of this infectiousness is thought to be as much as 26 times greater than that observed during chronic HIV infection, and may be further elevated in patients with coexisting sexually transmitted infections (STI). The sexual partners of acute HIV infection patients with STIs may be more vulnerable to HIV acquisition, because of genital tract inflammation and ulcerations. Data from international and South African studies demonstrate that STI patients are a high-risk population for acute HIV infection. However, most acute HIV infection cases remain clinically undiagnosed, and scoring algorithms offer little assistance to physicians and nurses in terms of improving their diagnostic ability. Laboratory testing of blood specimens remains the only effective means of diagnosis. Laboratory costs have been reduced through the use of pooling strategies for HIV nucleic acid detection, and algorithms that incorporate dual HIV rapid tests and ultrasensitive p24 antigen assays. The availability of these diagnostic tools and antiretroviral drugs means that there is a window of opportunity to enhance HIV prevention activities in South Africa. This can be achieved by screening STI patients for acute HIV infection, in order to initiate appropriate medical management, risk reduction counselling and partner notification.

Magnetic bead technology for viral RNA extraction from serum in blood bank screening

Nucleic acid amplification testing (NAT) was recently recommended by Brazilian legislation and has been implemented at some blood banks in the city of São Paulo, Brazil, in an attempt to reduce blood-born transmission of human immunodeficiency virus (HIV) and hepatitis C virus. ObjectiveManual magnetic particle-based extraction methods for HIV and HCV viral nucleic acids were evaluated in combination with detection by reverse transcriptase -polymerase chain reaction (RT-PCR) one-step. MethodsBlood donor samples were collected from January 2010 to September 2010, and minipools of them were submitted to testing. ELISA was used for the analysis of anti-HCV/HIV antibodies. Detection and amplification of viral RNA was performed using real-time PCR. ResultsOut of 20.808 samples screened, 53 samples (29 for HCV and 24 for HIV) were confirmed as positive by serological and NAT methods. ConclusionThe manual magnetic bead-based extraction in combination with real-time PCR detection can be used to routinely screen blood donation for viremic donors to further increase the safety of blood products.

Zero risk tolerance costs lives: loss of transplantable organs due to human immunodeficiency virus nucleic acid testing of potential donors

Patients' deaths due to the organ donor shortage make it imperative that every suitable organ be transplanted. False-positive results of tests for infection with the human immunodeficiency virus (HIV) result in lost organs. A survey of US organ procurement organizations collected the numbers of donors and ruled-out potential donors who had a positive result on an HIV test from January 1,2006, to October 31, 2008. Sixty-two percent of US organ procurement organizations participated. Of the 12397 donor/nondonor cases, 56 (0.45%) had an initial positive result on an HIV antibody or HIV nucleic acid test, and only 8 (14.3%) of those were confirmed positive. Of the false-positive results, 50% were from HIV antibody tests and 50% were from HIV nucleic acid tests. Organs are a scarce, finite, and perishable resource. Use of HIV antibody testing has produced a remarkably safe track record of avoiding HIV transmission, with 22 years of nonoccurrence between transmissions. Because false positives occur with any test, including the HIV Ab test, adding nucleic acid testing to the standard donor testing panel doubles the number of false-positive HIV test results and thus the number of medically suitable donors lost. The required HIV antibody test is 99.99% effective in preventing transmission of the HIV virus. Adding the HIV nucleic acid test to routine organ donor screening could result in as many as 761 to 1551 unnecessary deaths of patients between HIV transmission events because medically suitable organs are wasted.

Zero Risk Tolerance Costs Lives: Loss of Transplantable Organs Due to Human Immunodeficiency Virus Nucleic Acid Testing of Potential Donors

Patients' deaths due to the organ donor shortage make it imperative that every suitable organ be transplanted. False-positive results of tests for infection with the human immunodeficiency virus (HIV) result in lost organs. A survey of US organ procurement organizations collected the numbers of donors and ruled-out potential donors who had a positive result on an HIV test from January 1,2006, to October 31, 2008. Sixty-two percent of US organ procurement organizations participated. Of the 12397 donor/nondonor cases, 56 (0.45%) had an initial positive result on an HIV antibody or HIV nucleic acid test, and only 8 (14.3%) of those were confirmed positive. Of the false-positive results, 50% were from HIV antibody tests and 50% were from HIV nucleic acid tests. Organs are a scarce, finite, and perishable resource. Use of HIV antibody testing has produced a remarkably safe track record of avoiding HIV transmission, with 22 years of nonoccurrence between transmissions. Because false positives occur with any test, including the HIV Ab test, adding nucleic acid testing to the standard donor testing panel doubles the number of false-positive HIV test results and thus the number of medically suitable donors lost. The required HIV antibody test is 99.99% effective in preventing transmission of the HIV virus. Adding the HIV nucleic acid test to routine organ donor screening could result in as many as 761 to 1551 unnecessary deaths of patients between HIV transmission events because medically suitable organs are wasted.

HIV Load Testing with Small Samples of Whole Blood

Access to human immunodeficiency virus (HIV) viral load (VL) testing is of paramount importance for the success of antiretroviral therapy treatment campaigns throughout the world. In many countries, limited laboratory infrastructure and transport capacities preclude a substantial number of people infected with HIV from accessing the necessary testing. Point-of-care diagnostic testing methods for those with HIV infection provide a compelling solution to addressing this challenge. To facilitate ease of use in such tests, finger-stick whole blood (WB) would constitute an ideal sample type if test performance equivalent to laboratory testing could be ensured. To determine the diagnostic sensitivity of a VL assay based on small volumes of WB, we analyzed 1,094 sample pairs of 1 ml of plasma and 10 microl of WB from donors confirmed to be HIV positive. The probability of detecting HIV nucleic acids in 10 microl of blood was 59.3% (95% confidence interval, 54.9 to 63.6%), 85.1% (80.0 to 90.2%), 91.5% (88.1 to 95%), and 100% when the corresponding plasma samples had an undetectable VL, a detectable VL less than 40 viral copies/ml (cp/ml), a VL between 40 and 4,000 cp/ml, and a VL greater than 4,000 cp/ml, respectively. Capillary blood and venous blood yielded comparable diagnostic sensitivities. Furthermore, our data indicate that WB could be used to monitor VL changes after highly active antiretroviral therapy (HAART) started. Thus, we have demonstrated the feasibility of small volumes of venous and finger-stick WB as valid samples for VL testing. This approach should facilitate the development of robust point-of-care HIV VL tests.

Public Health Rationale for Rapid Nucleic Acid or p24 Antigen Tests for HIV

Rapid diagnostic tests that might be capable of detecting human immunodeficiency virus (HIV) antigens or nucleic acids represent the possibility of merging 2 key advancements in HIV testing: rapid testing and detection of acute HIV infection. In this article, we review the public health goals of rapid HIV testing and acute HIV testing and explore how rapid tests to directly detect HIV antigens or nucleic acids might alter current approaches to HIV case identification in clinical and public health screening settings. We discuss the specific types of HIV screening programs and settings in which direct viral rapid testing would offer an important advantage. Finally, we suggest priorities in operations research that must be achieved to pave the way for the future introduction of direct rapid viral testing technologies in the HIV testing marketplace.

Laboratory diagnostics for HIV infection

Laboratory diagnosis of human immunodeficiency virus (HIV) infection is fundamental for detecting and monitoring infection. Many diagnostic tools are available that are based on both detection of HIV-specific antibodies and virus antigen, or nucleic acid. As technology evolves, HIV testing assays are being improved providing better sensitivity and specificity. In this short review, we summarize the common and new methodologies that are being used in laboratories, from the HIV antibody-based assays to the new tests for the detection of HIV nucleic acids.

Incremental detection of HIV infections by the HIV antigen/antibody combination assays: An Australian experience

Detection of acute cases of human immunodeficiency virus (HIV) infection by the direct detection of HIV antigen or HIV nucleic acid assays is well known with an estimated 5-9 days reduction in the pre-seroconversion 'window period' by the detection of HIV specific antibodies. The aim of this study was to observe the impact following routine introduction of a screening assay which simultaneously detects HIV (type 1 & 2) antigen and antibody on the yield of acute HIV infection in multiple sites servicing different patient populations with a varying range of risk factors associated with HIV acquisition. During the first year (2003-2004), a total of 27 cases of acute HIV-1 infection were identified by the HIV-1/2 Ab/Ag combo test which were confirmed to be detectable for HIV antigen only that may have gone undetected should an HIV-1/2 antibody only assay have been used. Specimens referred from higher HIV case load centers were more likely to have provided relevant clinical information consistent with acute retroviral syndrome and relevant history of risk however there were numerous cases where no clinical information was provided. This study shows that routine introduction of HIV-1/2 antigen/antibody screening assays increases the identification of acute cases of HIV infection in low prevalence setting and may represent an important tool for enhanced surveillance of incident HIV infection and opportunities for prevention.