Clinical diagnostic services
HIV-1 Viral Load Testing
Quantitative monitoring in the control
of HIV
What is HIV-1 viral load testing?
HIV-1 viral load refers to the number of viral RNA genomes found in each mL of blood. In general terms the greater the amount of virus in the blood the more serious the disease is likely to be. Viral load often correlates with the level of CD4 cells in the patient and can indicate the likelihood of progression towards AIDS.
HIV-1 viral load testing is intended for use in conjunction with clinical presentation and other laboratory markers of disease progress for the clinical management of HIV-1 infected patients.
HIV-1 viral load testing is not intended to be used as a screening method for HIV-1 or as a diagnostic test to confirm the presence of HIV-1 infection.
Why choose the test?
- High Sensitivity – consistently capable of detecting and measuring viral load levels down to 50 copies/mL.
- High Specificity – positive only when HIV-1 is present and provides reproducible results.
- Combined with a CD4 cell count – the ability to measure HIV-1 viral load levels and monitor how they change over time has made it possible to:
track how effective the body is at fighting HIV-1 and estimate the risk of developing AIDS while judging the effectiveness of therapy. - Monitor the appearance of resistance.
- State-of-the art technology – Highly accurate, fully
validated molecular testing is employed giving
quantitative results. - CE marked and FDA approved tests.
- Lab21 Clinical Virology expertise.
What technique is used in the Viral Load assay?
HIV-1 RNA is quantitated by nucleic acid amplification using Polymerase Chain Reaction (PCR). EDTA anti-coagulated plasma is collected for analysis and Reverse transcription (RT) of target RNA is carried out to generate complimentary DNA (cDNA). PCR is then performed on cDNA and the amplified products are then hybridised to target specific olignucleotide probes. The hybridised probes along with the amplified products are then detected and quantified by colorimetric methods.
What tests are performed?
Depending on the time from initial diagnosis, anti-retroviral therapy regime and previous viral load result, the following levels of HIV-1 RNA can be detected using the corresponding test:
- HIV-1 viral load (standard) – measuring range between 400-750,000 copies/mL.
- HIV-1 (ultrasensitive) – measuring range between 50- 100,000 copies/mL.
- HIV-1 viral load (highly ultrasensitive) – measuring approximately greater than 10 copies/mL (research use only).
What is included in the report?
Results of this test will be sent to the GP or clinical
specialist. HIV-1 viral load is reported as the number of
HIV-1 viral particles in each millilitre of blood plasma
(reported as ‘copies/mL’).
How does the testing service work?
Product
sheet PDF
How do patients benefit?
The test can be used to assess patient prognosis by measuring the baseline HIV-1 RNA level or to monitor the effects of antiretroviral therapy by measuring changes in plasma HIV-1 RNA levels during the course of antiretroviral treatment.
Viral load is an important sign of how well the goal of therapy is being met; keeping the virus under control or suppressed for as long as possible.
The most important use of viral load measurement is to monitor the appearance of antiviral drug resistance. If a therapy is effective the viral load should disappear and may become undetectable. However, if the viral load starts to increase during therapy, this is very likely to indicate the appearance of resistance and immediate alteration of therapy is required.
From receipt of the patient sample at our laboratory, a fully interpreted HIV-1 viral load report will be sent to the clinician within 4 working days.
