Contacts
To order tests, or for more information:

International
Virco Belgium NV +32-15-286-320, Virco UK Ltd +44-1223-728800,
Virco Ireland Ltd +353-1-824-2700

United States
Virco Lab Inc 1-410-558-7031 or 1-800-371-8302, or

The LabCorp Center for Molecular Biology and Pathology
1-800-533-0567, ext. 3132

www.vircolab.com

Assay Names	Genotype	GENChec™ VirtualPhenotype™ quantitative analysis of drug resistance from genotype
	Phenotype	Antivirogram®
Collaborators/Distributors		ARUP The BC Centre for Excellence in HIV/AIDS (Vancouver) Chelsea and Westminster Hospital (London) Gilead (marketing only) Laboratory Corporation of America Quest Diagnostics SRL (Japan)
Availability		Commercially available.
Regulatory Status		United States: CLIA certified and CAP, New York State and Maryland accredited. The assays are non-kit-based.** The FDA does not currently regulate non-kit-based tests through published regulations or site inspections. Outside United States: ISO 9000 (NBN-EN45001) accreditation label through Beltest.
Proficiency Testing Programs		Virco
Clinical Trials		Content in development.
Financial Assistance		No

ASSAY INFORMATION

Genotypic	Phenotypic	Codons Interrogated		Turnaround time		Sensitivity
GENChec™	Antivirogram®	RT	PI	GENChec™	Antivirogram®	GENChec™	Antivirogram®
Full sequence assay	Recombinant	1–400	1–99	14 days	21–28 days	1,000 copies/mL	1,000 copies/mL

METHODOLOGY

Genotype
GENChec™: Viral RNA is extracted from plasma and amplified through RT-PCR. The products undergo automated dye terminator sequencing of the entire protease and up to codon 400 of the reverse transcriptase genes. Proprietary software is then used to compare the sequences with wild type viral sequences to determine the presence of any mutations.

VirtualPhenotype™
The VirtualPhenotype™ is a system for deriving quantitative predictions of phenotypic resistance from the genotype (as determined by Virco/(GENChec™ or other lab/assay). When a genotype is determined, the sequence is fed into a proprietary software system. This system identifies all the mutations relating to each drug and then interrogates a database of approximately 100,000 genotypes and phenotypes for genotypes from previous samples that match these mutations. When all the matches have been identified, the software retrieves the corresponding phenotypes for these samples and, for each drug, averages the data for all the matches. This produces a VirtualPhenotype™, reported as a "fold change in IC₅₀" for each drug. Each such determination is typically based on data from hundreds or thousands of real phenotypes with the same patterns of mutations. External labs and clinicians can order VirtualPhenotype™ analysis of previously determined DNA sequences by submitting sequence along with Virco requisition.


Phenotype
Antivirogram^®: HIV RNA is extracted and protease and reverse transcriptase genes out to codon 400 are converted to cCDNA by reverse transcription. The DNA is amplified using PCR. An HIV clone without protease and RT regions is created, and both the HIV clone and the amplified patient PR-RT DNA are introduced to CD4+ cells. The cells produce recombinant virus containing the patient’s viral PR-RT sequence. Different concentrations of all available drugs are placed in microwell plates, and set dilutions of recombinant virus and CD4+ cells with reporter gene systems are added to each well. After incubation, the amount of HIV replication in each concentration of drug is measured by a computerized system, and the susceptibility of the patient virus to each drug is calculated as the concentration of drug required to inhibit virus growth by 50% (IC₅₀). The IC₅₀ of the patient virus is then compared to the IC50 of fully susceptible, non-mutated wild-type virus. Supplies a quantitative measure of viral resistance to all available drugs expressed in terms of the IC₅₀.


REPORT INFORMATION

Report	Drug Resistance Interpretation
Genotype	No	GENChec™ does not include interpretation. GENChec™ is provided mainly for sequence determination prior to VirtualPhenotype™ analysis.
VirtualPhenotype™	Yes	The VirtualPhenotype™ is a system for deriving quantitative predictions of phenotypic resistance from the genotype. Although a genotypic test, the interpretation for the VirtualPhenotype™ expresses the resistance of the patient’s virus to a drug as the average fold change in IC50 associated with the mutational pattern of the sample virus; e.g., if the determined amount of drug required to inhibit the growth of the sample virus is 10 times as much as need to inhibit wild-type virus, there has been a 10-fold change in IC50. Drug-specific results are color coded to provide an interpretation of reported fold changes: "within normal susceptibility" (green, sensitive) or "above normal susceptibility" (red, resistant) for each drug. Sample Report: http://www.vircolab.com/services/virtualphenotype/index.cfm# virtualphenotype_report
Phenotype	Yes	The report for the Antivirogram® describes the resistance of sample virus as the fold change in IC50 compared to wild-type HIV-1. Results are then interpreted relative to "clinically relevant" susceptibility/resistance cutoffs for each drug (e.g., 4-fold increase in IC50 for AZT).* In this way, for a given drug (e.g., AZT), the sample virus is classified as being either within (< 4-fold) or above ( 4-fold) the normal susceptible range with approximately 97.5% confidence. If a cutoff has been approved by regulatory authorities for inclusion in the label for a drug, then this cutoff also appears on the report. Fold changes in IC50 detected for each drug are also displayed as bars on a log scale of fold change in IC50. These bars are color coded to indicate whether the sample virus is within the normal susceptible range (green stripes), above the normal susceptible range (red) or above the normal susceptible range but below the clinical cutoff (orange). Sample Report: http://www.vircolab.com/services/antivirogram/index.cfm# antivirogram_report

Return to Test Information Table - Genotypic

Return to Test Information Table - Phenotypic