Test Catalog

Test Id : HIRGT

HIV-1 RNA Quantification with Reflex to HIV-1 Genotypic Drug Resistance to Protease and Reverse Transcriptase Inhibitors, Plasma

Useful For
Suggests clinical disorders or settings where the test may be helpful

Quantifying plasma HIV-1 RNA levels (viral load) in individuals living with HIV, including children, followed by identification of genotypic mutations associated with viral resistance to inhibitors of HIV-1 reverse transcriptase and protease

 

Guiding initiation or change of combination antiretroviral therapy in individuals, including children, living with HIV

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
HIVPR HIV-1 Genotypic PR-RT Resistance, P Yes No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If HIV-1 RNA level is 500 copies/mL or higher, then HIV-1 genotypic drug resistance mutation testing will be performed at an additional charge.

 

The following algorithms are available in Special Instructions:

-HIV Testing Algorithm (Fourth-Generation Screening Assay), Including Follow-up of Reactive Rapid Serologic Test Results

-HIV Treatment Monitoring Algorithm

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Real-Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

HIV-1 RNA Reflex Geno PR-RT Resist, P

Aliases
Lists additional common names for a test, as an aid in searching

AIDS (Acquired Immune Deficiency Syndrome)

HIV (Human Immunodeficiency Virus)

HIV Drug Resistance

HIV Genotyping

HIV Genotypic Drug Resistance

HIV Mutation Analysis

HIV Resistance Mutation Analysis

HIV viral load

HIV-1 Drug Resistance

HIV-1 Genotyping

HIV-1 Genotypic Drug Resistance

HIV-1 Mutation Analysis

HIV-1 Resistance Mutation Analysis

HIV-1 PCR

HIV-1 Quantitation, PCR

HIV-1 RNA

HIV-1 viral load

Human Immunodeficiency Virus, PCR

PCR, HIV-1 Quantitation

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If HIV-1 RNA level is 500 copies/mL or higher, then HIV-1 genotypic drug resistance mutation testing will be performed at an additional charge.

 

The following algorithms are available in Special Instructions:

-HIV Testing Algorithm (Fourth-Generation Screening Assay), Including Follow-up of Reactive Rapid Serologic Test Results

-HIV Treatment Monitoring Algorithm

Specimen Type
Describes the specimen type validated for testing

Plasma EDTA

Shipping Instructions

1. Ship specimen frozen on dry ice.

2. If shipment will be delayed for >24 hours, freeze plasma specimen at -20 to -80 degrees C until shipment on dry ice.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Supplies: Aliquot Tube, 5 mL (T465)

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

2 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Plasma EDTA Frozen (preferred) 35 days
Refrigerated 5 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Quantifying plasma HIV-1 RNA levels (viral load) in individuals living with HIV, including children, followed by identification of genotypic mutations associated with viral resistance to inhibitors of HIV-1 reverse transcriptase and protease

 

Guiding initiation or change of combination antiretroviral therapy in individuals, including children, living with HIV

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If HIV-1 RNA level is 500 copies/mL or higher, then HIV-1 genotypic drug resistance mutation testing will be performed at an additional charge.

 

The following algorithms are available in Special Instructions:

-HIV Testing Algorithm (Fourth-Generation Screening Assay), Including Follow-up of Reactive Rapid Serologic Test Results

-HIV Treatment Monitoring Algorithm

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

HIV-1 is an RNA virus that infects human host cells and is then converted to complementary DNA (cDNA) by the action of viral reverse transcriptase. HIV-1 is the causative agent of AIDS, a severe, life-threatening condition.

 

Currently, 2 types of HIV: HIV type 1 (HIV-1) and HIV type 2 (HIV-2), are known to infect humans. HIV-1 has been isolated from patients with AIDS, AIDS-related complex, and 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. HIV-2 has been isolated from infected patients in West Africa and it appears to be endemic only in that region. However, HIV-2 also has been identified in individuals who have lived in West Africa or had sexual relations with individuals from that geographic region. HIV-2 is similar to HIV-1 in its morphology, overall genomic structure, and ability to cause AIDS.

 

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
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Undetected

Interpretation
Provides information to assist in interpretation of the test results

This assay has a plasma HIV-1 RNA quantification result range of 20 to 10,000,000 copies/mL (1.30-7.00 log copies/mL).

 

An "Undetected" result indicates that the assay was unable to detect HIV-1 RNA within the plasma specimen.

 

A result of "<20 IU/mL" indicates that HIV-1 RNA is detected, but the level present is less than the lower quantification limit of this assay. Due to the increased sensitivity of this assay, patients with previously low or undetectable HIV-1 viral load may show increased or detectable viral load with this assay. However, the clinical implications of a viral load below 20 copies/mL remain unclear. Possible causes of such a result include very low plasma HIV-1 viral load present (eg, in the range of 1-19 copies/mL), very early HIV-1 infection (ie, less than 3 weeks from time of infection), or absence of HIV-1 infection (ie, false-positive).

 

A result of ">10,000,000" with the result comment of "HIV-1 RNA level is >10,000,000 copies/mL (>7.00 log copies/mL). This assay cannot accurately quantify HIV-1 RNA above this level" indicates that HIV-1 RNA is detected, but the level present is above the upper quantification limit of this assay.

 

For the purpose of monitoring patient's response to antiretroviral therapy, the US Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents defines virologic failure as a confirmed viral load of greater than 200 copies/mL, which eliminates most cases of viremia resulting from isolated blips or assay variability. Confirmed viral load rebound (ie, >200 copies/mL) on 2 separate tests obtained at least 2 to 4 weeks apart should prompt a careful evaluation of patient's tolerance of current drug therapy, drug-to-drug interactions, and patient adherence.

 

If the viral load is greater than or equal to 500 copies/mL, genotypic antiviral drug resistance mutation analysis is performed automatically at an additional charge.

 

Genotype for drug resistance:

Codon sequences of the patient's HIV-1 reverse transcriptase and protease genes are compared with those in a database of known antiretroviral drug resistance mutations provided in the assay manufacturer's software application. Results are provided that highlight those codon changes associated with specific drug resistance. These mutations are categorized and reported.

 

"Susceptible (SUSC)" indicates that the genotypic mutations present in patient's HIV-1 strain have not been associated with resistance to the specific drug in question.

 

"Resistant (RESIST)" indicates that genotypic mutations detected have been associated with maximum reduction in susceptibility to the specific drug.

 

"Possible resistance (PR)" indicates that genotypic mutations detected have been associated with 1 or both of the following outcomes:

-Diminished virologic response in some, but not all, patients having virus with these mutations

-Intermediate decrease in susceptibility of the virus to the specific drug

 

"Unable to genotype" result indicates that the sequence data obtained are of poor quality to determine the presence or absence of genotypic resistant mutations in the patient's HIV strain. Probable causes of such poor sequence data include polymorphism in the region of the sequencing primers interfering with primer binding and subsequent sequencing reaction, or low viral load (ie, <500 copies/mL).

 

"Inconclusive" result indicates inability of the assay to reliably determine antiviral resistance because of the presence of polymerase chain reaction inhibitors or ambiguous or incomplete viral target sequences generated from the assay.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The HIV-1 RNA detection and quantification assay is not licensed by the 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 to be 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 (> or =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 that are 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.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Centers for Disease Control and Prevention and Association of Public Health Laboratories. Laboratory testing for the diagnosis of HIV infection: Updated recommendations. June 27, 2014. Available at http://stacks.cdc.gov/view/cdc/23447

2. Gunthard HF, Saag MS, Benson CA, et al: Antiretroviral drugs for treatment and prevention of HIV infection in adults: 2016 recommendations of the International Antiviral Society-USA Panel. JAMA. 2016 Jul 12;316(2):191-210

3. Panel on Antiretroviral Guidelines for Adults and Adolescents: Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. US Department of Health and Human Services. October 17, 2017. Updated December 18, 2019. Accessed May 13, 2021. Available at https://aidsinfo.nih.gov/guidelines/html/1/adult-and-adolescent-arv/3/tests-for-initial-assessment-and-follow-up

4. Wensing AM, Calvez V, Gunthard HF, et al: 2017 Update of the drug resistance mutations in HIV-1. Top Antivir Med. 2017;24(4):132-141

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

The cobas HIV-1 assay is an FDA-approved, in vitro nucleic acid amplification test for the quantification of HIV-1 RNA in human plasma using the cobas 6800 System or cobas 8800 System for fully automated viral nucleic acid extraction (generic silica-based capture technique) and automated amplification and detection of the viral nucleic acid sequence. This PCR assay amplifies sequences within the gag gene and LTR region of the HIV-1 genome and generates amplification products that are detected and quantified in real-time with 2 sequence-specific TaqMan probes. A non-HIV armored RNA quantitation standard (RNA-QS) is introduced into each specimen during sample preparation to serve as internal control for nucleic acid extraction and PCR amplification / detection processes. Fluorescent reporter dye-labeled TaqMan probes hybridized to the complementary HIV-1 target sequences and RNA-QS sequence undergo hydrolysis during PCR amplification step to generate fluorescent signal detected in 2 different dye channels. Concentration of the HIV-1 RNA in a patient's plasma sample is determined by a ratio of the intensity of the fluorescent dye from the cleaved HIV-1 target sequence probes and that from the RNA-QS target probe detected throughout the PCR process.(Package insert: cobas HIV-1 - Quantitative nucleic acid test for use on the cobas 6800/8800 Systems; Roche Molecular Systems, Inc., Branchburg, NJ; Doc rev. 1.0, 01/2016)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

HIRGT: Monday through Saturday.

HIVPR: Varies

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 10 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

60 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87536-HIV-1 Quantification

87901-HIV-1 genotypic drug resistance (if appropriate)

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports