HIV viral load

Diagnostic Use

Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). It can be transmitted through sexual contact, exposure to infected blood or blood products, or from an infected mother to the fetus. Acute HIV syndrome, characterized by flu-like symptoms, develops three to five weeks after initial infection and is associated with high levels of viremia. Within four to six weeks of the onset of symptoms, HIV specific immune response (ie presence of HIV antibodies) is detectable. After seroconversion, viral load in peripheral blood declines and most patients enter an asymptomatic phase that can last for years.

The diagnosis of HIV infection involves testing for the presence/absence of HIV-specific antigen and antibodies, please refer to the entry for HIV antibody (1 + 2), Blood.

Quantitative measurement of HIV-1 RNA levels in plasma has been shown to be an essential parameter in prognosis and management of HIV-1 infected individuals. Viral load monitoring of HIV-1 levels is considered the most reliable indicator of initial and sustained response to anti-retroviral therapy (ART) and should be obtained at the entry into care, at initiation and during therapy.

Decisions regarding changes in antiretroviral therapy are guided by monitoring changes in plasma HIV-1 viral load levels over time.
Virological response failure, which is suggestive of resistance to current antiretroviral therapies, is considered to occur when there is a persistently elevated HIV-1 viral load.

Department

Microbiology - Virology

Delphic Registration Code

THIV

Laboratory Handling

Phlebotomy

Dedicated EDTA tubes required, minimum 4mL whole blood

Registration

If sample arrives frozen, please ensure it does not thaw.

Separating

Please refer to separating guide in Additional Information section below

Laboratory

Testing available daily on routine weekdays.

Test Adds

Add-on requests for viral load testing are only able to be performed if other plasma viral loads have been requested as dedicated sterile samples are required. Viral loads cannot be added to samples previously processed for CBC testing. Please call Virology on ext 80356 to discuss

Synonyms

HIV quantitation
HIV titre
HIV RNA
HIV PCR
HIV Viral Load

Turnaround Time

3 days

Test Code

2744

Specimen Type

• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

5.0

No of Samples Required

2

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Minimum Sample Volume (ml)

2

Pre-testing Requirements

For paediatric patients, minimum volume required is 1.0mL of EDTA plasma. Please collect as close to 2.0mL of EDTA blood as possible to ensure there is enough plasma for testing.

Please refer to separating guidelines in the Additional Information section below. All viral loads are required to be received in the laboratory by 4.30pm on Friday.

Aliquot Instructions

Sample Type

• Plasma

Minimum Volume (ml)

2

Transport to Lab

Chilled (2 - 8 degrees Celsius)
Frozen

Additional Referral/Aliquot Information

If separated sample will arrive within 70 hours of collection, chilled transport is acceptable.
If this timeframe cannot be guaranteed, please send samples frozen.

Interpretation

Results are reported as HIV-1 RNA copies/mL.

An infectious disease physician should be consulted for interpretation of results.

Test Method

Detection and quantification of Human deficiency virus type-1 (HIV-1) RNA by RT-PCR: Abbott Alinity m platform.

Non-Funded Test Cost

$602.9 (Exclusive of GST)

Billing Code

2744

This assay is not a screening test for HIV. It is a quantitative assay for monitoring disease activity and/or response to therapy.

Test Availability - Turnaround times are based on longest expected results for specimens received end of week and tested following week. Expect samples received M-Th to have 24 hr turnaround. Testing is performed on Abbott Alinity M platform.

Add-on requests for viral load testing are only able to be performed if other plasma viral loads have been requested as dedicated sterile samples are required. Viral loads cannot be added to samples previously processed for CBC testing.

After testing is complete samples are stored frozen for 6 months.
Resistance genotyping can be added to a sample if there is sufficient volume and testing requirements are met. Please call Virology to discuss add-on testing.

Resources

• Viral Load collection and separation guidelines (198 KB)

Contact Information

Enquiry Form