Human Immunodeficiency Virus

Modern diagnostic technologies for HIV

Novel diagnostic technologies, including nanotechnology, microfluidics, -omics science, next-generation sequencing, genomics big data, and machine learning, could contribute to meeting the UNAIDS 95-95-95 targets to end the HIV epidemic by 2030. Novel technologies include multiplexed technologies (including biomarker-based point-of-care tests and molecular platform technologies), biomarker-based combination antibody and antigen technologies, dried-blood-spot testing, and self-testing. Although biomarker-based rapid tests, in particular antibody-based tests, have dominated HIV diagnostics since the development of the first HIV test in the mid-1980s, targets such as nucleic acids and genes are now used in nanomedicine, biosensors, microfluidics, and -omics to enable early diagnosis of HIV. These novel technologies show promise as they are associated with ease of use, high diagnostic accuracy, rapid detection, and the ability to detect HIV-specific markers. Additional clinical and implementation research is needed to generate evidence for use of novel technologies and a public health approach will be required to address clinical and operational challenges to optimise their global deployment.

Difficulties of Identifying the Early HIV Antibody Seroconversion Period Depending on the Confirmatory Assay

BACKGROUND

Identification of HIV infection at the early stage is valuable for patient management, for prevention, and for research purposes. In practice, identification of a recent HIV infection at diagnosis proves challenging after HIV antibody seroconversion but can be suspected using Western blots (WBs) or immunoblots (IBs) as confirmatory assays.

METHODS

Five commercially available confirmatory assays were compared using 43 samples from recently infected individuals. This included 2 WBs (New LAV Blot I, Biorad, and HIV Blot 2.2, MP Biomedicals), 2 IBs (INNO-LIA HIV I/II, Fujirebio, and RecomLine HIV-1 & HIV-2, Mikrogen Diagnostik), and 1 immunochromatographic single-use assay (Geenius HIV1/2 supplemental assay, Biorad).

RESULTS

Following the manufacturer's recommendations for interpretation, the 2 WBs led to indeterminate results for 30% and 42% of the samples, suggesting recent infection, compared with 2%-7% for the 3 other assays. When interpreted based on the Fiebig classification, concordant stages were observed in 42% of samples, and only 49% were classified as early seroconversion by all 5 assays. For the remaining specimens, the distinction with chronic infection was highly variable depending on the assay (5%-100%).

CONCLUSIONS

Clinical laboratories must consider this variability, which must be kept in mind both for initial diagnosis and for multicenter studies for which inclusion criteria refer to serological profiles by confirmatory assays.

Companion and complementary diagnostics for infectious diseases

INTRODUCTION

Companion diagnostics (CDx) are important in oncology therapeutic decision-making, but specific regulatory-approved CDx for infectious disease treatment are officially lacking. While not approved as CDx, several ID diagnostics are used as CDx. The diagnostics community, manufacturers, and regulatory agencies have made major efforts to ensure that diagnostics for new antimicrobials are available at or near release of new agents.

AREAS COVERED

This review highlights the status of Complementary and companion diagnostic (c/CDx) in the infectious disease literature, with a focus on genotypic antimicrobial resistance testing against pathogens as a class of diagnostic tests.

EXPERT OPINION

CRISPR, sepsis markers, and narrow spectrum antimicrobials, in addition to current and emerging technologies, present opportunities for infectious disease c/CDx. Challenges include slow guideline revision, high costs for regulatory approval, lengthy buy in by agencies, discordant pharmaceutical/diagnostic partnerships, and higher treatment costs. The number of patients and available medications used to treat different infectious diseases is well suited to support competing diagnostic tests. However, newer approaches to treatment (for example, narrow spectrum antibiotics), may be well suited for a small number of patients, i.e. a niche market in support of a CDx. The current emphasis is rapid and point-of-care (POC) diagnostic platforms as well as changes in treatment.

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.