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HelpOrder Code HIVDR HIV-1 Genotypic Drug Resistance to Reverse Transcriptase, Protease, and Integrase Inhibitors, Plasma
Ordering Guidance
This test is intended for detection and identification of drug resistance-associated HIV-1 genotypic mutations in plasma specimens of individuals prior to or while receiving combination antiretroviral therapy.
Prior to requesting this test, patients must have a confirmed plasma HIV-1 RNA level (ie, viral load) of 1000 copies/mL or higher within the preceding 30 days. HIVQN / HIV-1 RNA Detection and Quantification, Plasma is available to provide this prerequisite test result. Alternately, if the patient's viral load is unknown, order HIQDR / HIV-1 RNA Quantification with Reflex to Genotypic Drug Resistance to Reverse Transcriptase, Protease, and Integrase Inhibitors, Plasma, which will perform viral load followed by genotype, if appropriate.
For initial diagnosis of HIV, order HIVDX / HIV-1 and HIV-2 Antigen and Antibody Diagnostic Evaluation, Plasma.
Additional Testing Requirements
Shipping Instructions
If shipment will be delayed for more than 24 hours, freeze plasma specimen at -70° C (up to 60 days) until shipment on dry ice.
Necessary Information
The following ask-at-order entry question must be answered at the time of test ordering (mark answer on the test request form if not ordering electronically):
HIV-1 RNA level copies/mL in last 30 days = (select answer option)
<1000
1000 to 1,000,000
1,000,001 to 10,000,000
>10,000,000
Note: Test requests for submitted specimens with less than 1000 copies/mL (not sufficient amount for testing), “No,†or no response entered will be canceled.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 2.2 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.
Additional Information: Specimens submitted for HIV-1 genotyping must contain 1000 copies/mL or more of HIV-1 RNA.
Useful For
Identifying 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
Method Name
Reverse Transcription Polymerase Chain Reaction (RT-PCR) followed by Targeted Next-Generation Sequencing (NGS)
Reporting Name
HIV-1 Genotypic Drug Resistance, PSpecimen Type
Plasma EDTASpecimen Minimum Volume
0.8 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma EDTA | Frozen (preferred) | 60 days | |
| Refrigerated | 7 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
An interpretive report will be provided.
Method Description
This test utilizes the US Food and Drug Administration-approved, commercially available Sentosa SQ HIV-1 Genotyping Assay, which is a next-generation sequencing assay based on a "sequencing by synthesis" method. The assay is designed to generate 2 amplicons (approximately 1500 base pairs [bp] and approximately 1000 bp in length) spanning the PR / RT- and INT-coding regions, respectively, of the HIV-1 genome for sequencing. Codon positions 1 to 99, 1 to 387, and 1 to 288 in the PR-, RT-, and INT-coding regions, respectively, are subsequently analyzed by the assay software for clinically relevant codon substitutions.
Clinical plasma specimens are subjected to automated HIV-1 RNA extraction and purification, followed by reverse-transcription polymerase chain reaction of HIV-1 target sequences, with both a system control and a positive control included in each assay run for quality control purposes. Automated DNA library preparation is performed using the amplified products, including enzymatic shearing, adapter ligation, purification, and normalization, prior to DNA template preparation and sequencing. Sequencing reactions are conducted with the Sentosa SQ301 sequencer, and the assembled sequence data are analyzed using proprietary analysis and interpretive software applications. HIV-1 antiviral drug-resistance interpretations are based on algorithms implemented in the most current version of the Stanford University HIV Drug Resistance Database (HIVdb; Stanford University) using a 5% variant detection cutoff threshold set by the assay manufacturer.(Instruction manual: Sentosa SQ HIV-1 Genotyping Assay User Manual. Vela Diagnostics; Version 1.3, 05/2023)
Day(s) Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
0219U
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Testing Algorithm
For information see HIV Treatment Monitoring Algorithm