Virological tests

Philip Cunningham NSW State Reference Laboratory for HIV, St Vincent’s Hospital, Sydney NSW Last reviewed: May 2019 Introduction The diagnosis of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) infection is usually made by the detection of circulating antibodies in blood. Antibodies are identified by the use of a screening test (standard test), usually …

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HIV antibody enzyme immunoassay Because of its rapidity, sensitivity and low cost, the enzyme immunoassay (EIA) is the standard screening tool for HIV infection[1]. Synthetic and native HIV antigens, fixed on a solid phase, are exposed to and bound by HIV antibodies in test serum. These antibodies are then detected by a second antibody to …

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HIV-2 infection is rare in Australia and antibodies to HIV-2 proteins in most sera from people with HIV-2 infection will cross-react with HIV-1 proteins in Western Blot assays. Specific HIV-2 Western Blot assays can be used to confirm HIV-2 infection and distinguish it from HIV-1. However, the cross-reactivity between HIV-1 and HIV 2 is often …

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HIV RNA quantification (or viral load) is a critical tool in the management of HIV disease. Detection of HIV RNA can help provide a positive diagnosis of HIV infection in certain clinical situations, such as acute or neonatal infection, where standard serological testing is inappropriate or unclear. Quantification of HIV RNA levels allows and predicts …

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Tissue culture allows HIV to be expanded and propagated in vitro by its culture with donor peripheral blood mononuclear cells in the presence of stimulatory factors such as interleukin 2 (IL-2). Coculturing of patient peripheral blood mononuclear cells, or cells from other body compartments suspected to be infected with HIV, with stimulated donor peripheral blood …

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HIV shows a high rate of genomic evolution due to the error-prone nature of RT (which introduces random sequence changes into newly produced viral RNA)[23],  the high rate of viral production, and the rapid turnover of productively infected cells. For these reasons HIV strains rapidly develop resistance to antiretroviral monotherapy through the acquisition of mutations …

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HIV-1 uses one of two coreceptors for entry into cells: CCR5 and CXCR4. CCR5 inhibitors, block the CCR5 receptor, but not the CXCR4 coreceptor, reducing viral entry, replication and therefore plasma viral load. CCR5 inhibitors, of which maraviroc is the only one licensed, are only effective if a patient’s HIV uses CCR5 as its coreceptor.[34] …

Genotypic determination of HIV-1 CCR5/CXCR4 tropism Read More »

Abacavir hypersensitivity reaction (AHSR) affects 4-8% of patients with HIV-1 infection within the first 6 weeks of starting abacavir. It is usually characterised by fever, rash, abdominal pains and lethargy. Symptoms related to abacavir hypersensitivity reaction deteriorate with continued therapy and improve within 72 hours of abacavir discontinuation. Rechallenging with abacavir after a hypersensitivity reaction …

HLA-B*57:01 allele genotyping for assessing the risk of abacavir hypersensitivity reaction. Read More »

Silvester C, Healey DS, Cunningham P, Dax EM.  Multisite evaluation of four anti-HIV-1/HIV-2 enzyme immunoassays. Australian HIV Test Evaluation Group. J Acquir Immune Defic Syndr Hum Retrovirol 1995;8:411-9. Branson BM and Stekler JD Detection of Acute HIV Infection: We Can’t Close the Window. editorial commentary JID 2012;205:521 Stekler J,  Maenza J, Stevens CE,  Swenson PD: …

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