HIV-1 RNA Viral Load

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Testing Indications

HIV-1 RNA viral load testing is intended for the quantification of HIV-1 viral load in patients known to be HIV-1 positive. It is intended for use in conjunction with clinical presentation and other laboratory markers as an indicator of disease. This test can be used to assess patient prognosis by measuring baseline HIV-1 RNA level and as an aid in assessing viral response to antiretroviral treatment as measured by changes in plasma HIV-1 RNA levels.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
HIV-1 RNA Viral Load	HIV Viral Load Test Requisition	Whole blood^1,3	10 mL	EDTA or PPT³
HIV-1 RNA Viral Load	HIV Viral Load Test Requisition	EDTA Plasma^1,2	2.5 mL	EDTA or PPT

Submission and Collection Notes

Freshly drawn whole blood specimens (EDTA or PPT) may be stored and/or transported at 2°C - 25°C for up to 24 hours before centrifugation. Following centrifugation, remove plasma from cells immediately, and transfer plasma into sterile screw-capped cryovials.

Plasma can be stored and/or transported at 2°C - 8°C for up to 6 days after separation or at ≤-18°C for up to 12 weeks. If more extended storage of plasma specimens is required, they must be frozen at ≤ -60°C.

Unspun whole blood must be received at Public Health Ontario’s (PHO) Laboratory within 24 hours of collection before 2:00 p.m. Monday – Friday.

Limitations

The HIV-1 viral load assay is not intended to be used as a screening test for HIV-1 or as a diagnostic test to confirm the presence of HIV-1 infection.

Grossly haemolysed, icteric, lipemic or microbially contaminated plasma are not recommended for testing.

Storage and Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Place specimen in a biohazard bag and seal. It is recommended to ship specimens for testing to PHO’s laboratory immediately after collection or processing to avoid delays in testing.

Shipping of specimens shall be done by TDG certified individuals in accordance with TDG regulations.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

HIV-1 viral load is performed daily Monday to Friday.

Turnaround time is up to 6 business days from receipt by PHO Laboratory.

Test Methods

Specimens for HIV-1 RNA viral load are tested using the Roche cobas® HIV-1 Quantitative Assay on the cobas® 6800/8800 system. The cobas® HIV-1 assay is an in vitro nucleic acid amplification test for the quantitation of HIV-1 in EDTA human plasma of HIV-1 infected individuals. Please note that the cobas® HIV-1 viral load assay is more sensitive than the previous assay used at PHO (Abbott RrealTime HIV-1 Viral Load assay). Additional information regarding increased sensitivity and interpretations can be found here.

Interpretation

Results should be interpreted in the context of the patient’s clinical presentation, risk factors, and exposure history. The table below provides a general overview of HIV-1 RNA viral load results and interpretations.

Results	Interpretation
Not Detected	HIV-1 RNA not detected
<20 copies/mL	HIV-1 RNA detected below the lower limit of quantitation. Unable to quantify. (An exact value for HIV-1 viral load cannot be calculated as it is below the lower limit of quantitation of 20 copies/mL.)
20 - 10,000,000 copies/mL	Viral load will be reported in copies/mL.
>10,000,000 copies/mL	HIV-1 RNA detected above the upper limit of quantitation. Unable to quantify. (An exact value for HIV-1 viral load cannot be calculated as it is above the upper limit of quantitation of 10,000,000 copies/mL.)