Sign in →

Test Code HIVGD HIV-1 Genotypic Drug Resistance Sequencing (Plasma)

Clinical Indications

HIV-1 Genotypic Drug Resistance
Sequencing detects viral genomic mutations known to confer
resistance to antiretroviral therapies and provides an estimate of
susceptibility to medications including:

•Nucleoside reverse-transcriptase inhibitors (NRTI)
•Non-nucleoside reverse-transcriptase inhibitors (NNRTI)
•Protease inhibitors (PI)
•Integrase inhibitors (INI)

Susceptibility profile is determined based on the Stanford
University HIV Drug Resistance Database.
See the Stanford University website for a complete list of regions
evaluated, associated susceptibility and references:
http://hivdb.stanford.edu/pages/references.html.

Additional Test Codes

Epic Order Name: HIV1 GENOTYPIC
DRUG RESISTANCE
(aka HIVGD)
Sunquest Order Code: HIVGD
Epic Px Code: LAB2955

Specimen Collection Type

Preferred: PPT (pearl top EDTA)
Acceptable: Lavender (EDTA) or Yellow
(ACD solution)

Minimum Collection Volume

1.0 mL

Reference Range

Subtype of HIV-1 will be reported as
B, A, AE, AG, C, D or G. Mutations in the protease inhibitor,
reverse-transcriptase, and integrase genes will be reported as
indicating the mutation detected/None. Interpretation of gene
mutations and association with antiviral resistance will be
reported as Susceptible, Potential low-level resistance, Low-level
resistance, Intermediate resistance, or High-level resistance.

Critical Value

N/A

Interpretation

The HIV-1 Genotypic Drug Resistance
assay utilizes RT-PCR amplification with
primers in highly conserved viral genomic regions to amplify three
fragments covering HIV-1 subtypes B, A,
AE, AG, C, D, and G. These three regions include protease, a large
portion of reverse-transcriptase where resistance mutations have
been reported, and integrase. The fragments are purified and
sequenced using sequencing primers from conserved regions of the
fragments. The trimmed derived sequence is examined for resistance
mutations using the curated Stanford University HIV-1 Drug Resistance Database (Soo-Yon R. et. al.,
2003) and the REGA HIV-1 subtyping tool to determine the subtype (de
Oliveira T. et. al. 2005 and Alcantara LCJ. et. al. 2009). The Stanford University
HIV-1 Drug Resistance Database detects
mutations known to confer resistance to antiretroviral therapies.
Mutations are scored and these scores are converted to provide
qualitative results estimating susceptibility to medications. These
medications include nucleoside reverse-transcriptase inhibitors,
non-nucleoside reverse-transcriptase inhibitors, protease
inhibitors and integrase inhibitors. The actual quantitative score
can be provided to physicians at their request. The minimum
sequences that are required to generate a valid result are codons
10-93 for protease inhibitors (PI), codons 40-219 for nucleoside
reverse transcriptase inhibitors (NRTI),
codons 90-348 for non-nucleoside reverse transcriptase inhibitors
(NNRTI), and codons 51-263 for integrase
inhibitors.

Rejection Criteria

HIV-1 RNA
concentrations too low to allow antiviral resistance testing (see
above for minimum volume; patient must have a recent viral load
greater than 600 copies/mL), whole blood frozen, specimens beyond
their acceptable length of time from collection as listed in the
specimen stability, or specimen types other than those listed.

Specimen Availability for Add-on Testing

This test cannot be added on (Critical frozen)

Specimen Stability

Frozen: 7 days
Refrigerated: Unacceptable
Ambient: Unacceptable

Day(s) Performed

Varies

Performing Lab- Department

TUKHS-BH-Mail Outs

CPT Code

87901, 87906

LOINC Code

N/A

Test Alias

HIV Genotyping,
HIV Resistance
HIV-1 Drug Resistance Mutation
Analysis

HIV-1 Genotyping for Drug Resistance

Additional Information / Notes

Turnaround time: 4-6 business days from receipt of specimen
Note: If an HIV-1 viral load PCR test is ordered at the same time, the genotype
specimen will be held until this testing has been completed and a
sufficient viral load reported.