Advanced Technology Laboratory, Molecular Diagnostics

New Test Available: HIV-1 Quantitative RNA PCR

Effective September 23, 2016, Spectrum Health Regional Laboratory Molecular Diagnostics Department is pleased to announce that the HIV-1 Quantitative RNA PCR (Test Code #7125) has been added to our in-house test menu.

The Abbott RealTime HIV-1 assay uses reverse transcription-polymerase chain reaction (RT-PCR) technology combined with homogeneous real-time fluorescent detection on the Abbott m2000 system for quantitation of Human Immunodeficiency Virus type 1 (HIV-1) RNA in human plasma from HIV-1 infected individuals. The target sequence for the Abbott RealTime HIV-1 assay is in the pol integrase region of the HIV-1 genome, a region which is highly conserved.  The assay is intended for use in conjunction with clinical presentation and other laboratory markers for disease prognosis and for use as an aid in assessing viral response to antiretroviral treatment (ART) as measured by changes in plasma HIV-1 RNA levels.  This assay is not intended to be used as a donor screening test for HIV-1 or as a diagnostic test to confirm the presence of HIV-1 infection.

The assay is standardized against a viral standard from the Virology Quality Assurance (VQA) Laboratory of the AIDS Clinical Trial Group, and against the World Health Organization (WHO) 1st International Standard for HIV-1 RNA (NIBSC Code 97/656). The quantification range of Abbott’s HIV RealTime assay is 40 copies/mL (1.60 log copies/mL) to 10 million copies/mL (7.00 log copies/mL).  The assay can detect HIV below the stated lower limit of detection (LLOD) for the assay but will be reported as HIV-1 RNA less than 40 copies/mL.

Viral load is the most important indicator of initial and sustained response to ART and should be measured in all HIV-infected patients at entry into care, at initiation of therapy, and on a regular basis thereafter. The key goal of ART is to achieve and maintain durable viral suppression as decreases in viral load following initiation of ART are associated with reduced risk of progression to AIDS or death. Thus, the most important use of the viral load is to monitor the effectiveness of therapy after initiation of ART.

The minimal change in viral load considered to be statistically significant is a three-fold change (equivalent to a 0.5 log change). Individuals who are adherent to their therapy regimens and do not harbor resistance mutations to the component drugs can generally achieve viral suppression 8 to 24 weeks after ART initiation.

The “Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents” and the AIDS Clinical Trials Group (ACTG) now define virologic failure as the inability to achieve or maintain suppression of viral replication to an HIV RNA level <200 copies/mL. These patients should undergo resistance testing to aid in the selection of an alternative regimen with at least two active drugs.

Specimen Collection and Transport:

  1. Collect 6 mL whole blood in a pink-topped tube containing the anticoagulant EDTA.
  2. Centrifuge whole blood within 6 hours of collection and transfer plasma to a screw-capped transport tube with the patient specimen barcode label attached.
  3. Recommend specimens be transported frozen.

HIV-1 Result Interpretation:

 Not Detected (<40 copies/mL) *

Positive (40 to 10,000,000 copies/mL or >10,000,000 copies/mL)

Equivocal (HIV-1 RNA detected but less than 40 copies/mL) **

*     A result of “Not Detected” cannot be presumed to be negative for HIV-1 RNA.

**    Samples reported as “Equivocal” have detectable HIV-1 RNA but fall below the quantifiable range (<40 copies/mL).

For more information or questions, contact the Molecular Diagnostics Department, Pat Botma, Molecular Diagnostics Lead Technologist, or Dr. Cong Liu, Molecular Diagnostics Advisor, using the “Contact Us” link.

References:

Panel on Antiretroviral Guidelines for Adults and Adolescents. “Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents”. Department of Health and Human Services.

Available at http://www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf

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