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HelpTest ID HIQDR HIV-1 RNA Quantification with Reflex to Genotypic Drug Resistance to Reverse Transcriptase, Protease, and Integrase Inhibitors, Plasma
Ordering Guidance
This test is intended for quantification of HIV-1 RNA level in plasma specimens of individuals with known HIV-1 infection and for identification of drug resistance-associated HIV-1 genotypic mutations prior to or while receiving combination antiretroviral therapy.
Prior to requesting this test, the patient must have a known HIV-1 infection. The following tests are available to screen and confirm the HIV-1 infection status:
-HVCOP / HIV-1 and HIV-2 Antigen and Antibody Routine Screen, Plasma
-HIVDX / HIV-1 and HIV-2 Antigen and Antibody Diagnostic Evaluation, Plasma
If only HIV-1 genotypic mutation testing is needed, order HIVDR / HIV-1 Genotypic Drug Resistance to Reverse Transcriptase, Protease, and Integrase Inhibitors, Plasma.
Shipping Instructions
1. Ship specimen frozen on dry ice.
2. If shipment will be delayed for greater than 24 hours, freeze plasma specimen at -20 to -80° C until shipment on dry ice.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 3.6 mL
Collection Instructions:
1. Centrifuge blood collection tube and aliquot plasma into plastic vial per collection tube manufacturer's instructions (eg, centrifuge and aliquot within 2 hours of collection for BD Vacutainer tubes).
2. Freeze aliquoted plasma for shipment.
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T732) with the specimen.
Secondary ID
616917Useful For
Quantifying plasma HIV-1 RNA levels (viral load) in individuals (including children) with known HIV-1 infection, followed by identification of HIV-1 genotypic mutations associated with resistance to nucleotide and non-nucleoside reverse-transcriptase inhibitors protease inhibitors , and integrase strain transfer inhibitors
Guiding initiation or change of combination antiretroviral therapy in individuals, including children, with HIV-1 infection
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| HIVDR | HIV-1 Genotypic Drug Resistance, P | Yes | No |
Testing Algorithm
If HIV-1 RNA level is 1000 copies/mL or greater, then HIV-1 genotypic drug resistance mutation testing will be performed at an additional charge.
The following algorithms are available:
-HIV Prenatal Testing Algorithm, Including Follow-up of Reactive Rapid Serologic Test Results
Special Instructions
Method Name
Real-Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR)
Reporting Name
HIV-1 RNA Quant Reflex to Resist, PSpecimen Type
Plasma EDTASpecimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma EDTA | Frozen (preferred) | 55 days |
| Refrigerated | 5 days |
Clinical Information
HIV-1 is an RNA virus that infects human host cells and is then converted to complementary DNA by the action of viral reverse transcriptase. HIV-1 is the causative agent of AIDS, a severe, life-threatening condition, and the virus has been isolated from asymptomatic, infected individuals at high-risk for AIDS. Accounting for over 99% of HIV infections in the world, HIV-1 is transmitted by sexual contact, by exposure to infected blood or blood products, from an infected pregnant woman to fetus in utero or during birth, or from an infected mother to infant via breast feeding.
Multiple clinical studies of plasma HIV-1 viral load (expressed as HIV-1 RNA copies/mL of plasma) have shown a clear relationship of HIV-1 RNA copy number to stage of HIV-1 disease and efficacy of anti-HIV-1 therapy. Quantitative HIV-1 RNA level in plasma (ie, HIV-1 viral load) is an important surrogate marker in assessing the risk of disease progression and monitoring response to anti-HIV-1 drug therapy in the routine medical care of HIV-1-infected patients.
Studies have identified a number of mutations associated with antiviral resistance. Genotypic analysis allows identification of nucleotide changes associated with HIV drug resistance. When combination therapy fails, genotyping for drug resistance mutations may help direct appropriate changes in antiretroviral therapy and may result in at least a short-term benefit, as evidenced by viral load reduction.
Reference Values
Undetected
Cautions
The HIV-1 RNA detection and quantification assay is not approved by the US Food and Drug Administration (FDA) as a screening test for HIV-1 infection in donors of blood, human cells, tissues, or tissue products.
Although this quantitative HIV-1 RNA test is not FDA approved for diagnostic purposes, the US Department of Health and Human Services Panel on Antiretroviral Therapy and Medical Management of HIV-Infected Children recommends the use of molecular-based assays to detect HIV-1 RNA or proviral DNA for the diagnosis of HIV infection in infants younger than 18 months of age and born to HIV-infected mothers.
A single HIV-1 viral load test result should not be used as the sole criterion in guiding therapeutic decisions and intervention in the clinical care of HIV-1-infected patients. Viral load results should be correlated with patient symptoms, clinical presentation, and CD4 cell count. Due to the inherent variability in the assay, physiologic variation and concurrent illnesses in the infected patients, changes of less than 100-fold (<2 log) in plasma HIV-1 viral load should not be considered significant changes.
Viral load results below 20 copies/mL do not necessarily indicate absence of HIV-1 viral replication. Inhibitory substances may be present in the plasma specimen, leading to negative or falsely low HIV-1 RNA results. Improper specimen collection or storage may lead to negative or falsely lower plasma viral load results.
Although this commercial HIV-1 viral load assay is optimized for quantification of plasma viral load in HIV-1 infection due to HIV-1 groups M (subtypes A to H) and O strains, results generated from HIV-1 group O strains may be discordant (≥0.5 log copies/mL) with those obtained from other commercially available HIV-1 viral load assays. The assay is not reliable for quantifying plasma viral loads in infection caused by HIV-1 group N and HIV-2 strains.
ACD plasma specimens are not optimal for HIV-1 viral load testing because such plasma specimens show HIV-1 RNA levels approximately 15% lower than those collected in tubes containing EDTA. Plasma specimens stored frozen in plasma preparation tubes (PPT) are not suitable for HIV-1 viral load testing due to falsely high viral load results from release of intracellular HIV-1 nucleic acids (DNA and RNA) during the freezing process.
Day(s) Performed
Monday through Friday
Report Available
1 to 10 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
87536
0219U (if appropriate)