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Test Code LAB13392 Cytochrome P450 3A5 Genotype, Varies

Additional Codes

3A5Q

CYTOCHROME 

CYTOCHROME P450 3A5 *3, *6 AND *7 GENOTYPE

450


 

 


Ordering Guidance


Testing is available as the single gene assay (this test) and as a part of a psychotropic or focused pharmacogenomics panel.

 

If multiple pharmacogenomic genotype testing is desired, order PGXQP / Focused Pharmacogenomics Panel, Varies.

 

If genotype testing for psychotropic medications is desired, order PSYQP / Psychotropic Pharmacogenomics Gene Panel, Varies.



Additional Testing Requirements


In general, most drugs metabolized by CYP3A5 are also metabolized by CYP3A4 and usually to a greater degree than CYP3A5. For this reason, substrates of these 2 enzymes are sometimes listed together in publications and genotyping of both genes might be needed to fully understand the metabolism of these drugs and predict phenotype. If CYP3A4 genotyping is needed, order 3A4Q / Cytochrome P450 3A4 Genotype, Varies.



Specimen Required


Multiple genotype tests can be performed on a single specimen after a single extraction. See Multiple Genotype Test List for a list of tests that can be ordered together.

 

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred)/Refrigerated

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Swab Collection Kit (T786)

Specimen Volume: One swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient

 

Specimen Type: DNA

Container/Tube: 2 mL screw top tube

Specimen Volume: 100 mcL (microliters)

Collection Instructions:

1. The preferred volume is 100 mcL at a concentration of 50 ng/mcL.

2. Include concentration and volume on tube.

Specimen Stability Information: Frozen (preferred) 1 year/Ambient/Refrigerated


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Neurology Specialty Testing Client Test Request (T732)

-Therapeutics Test Request (T831)

-Renal Diagnostics Test Request (T830)

Secondary ID

610047

Useful For

Aids in optimizing treatment with tacrolimus and other drugs metabolized by cytochrome P450 3A5

Method Name

Polymerase Chain Reaction (PCR) With Allelic Discrimination Analysis

Specimen Type

Varies

Specimen Minimum Volume

Blood: 0.4 mL
Saliva: 1 swab

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Interpretation

An interpretive report will be provided.

 

The genotype, with associated star alleles, is assigned using standard allelic nomenclature as published by Pharmacogene Variation (PharmVar) Consortium.(1)

 

For additional information regarding pharmacogenomic genes and their associated drugs, see the Pharmacogenomic Associations Tables in Special Instructions. This resource also includes information regarding enzyme inhibitors and inducers, as well as potential alternate drug choices.

Method Description

Genomic DNA is extracted from whole blood or saliva. Genotyping for CYP3A5 alleles is performed using a polymerase chain reaction (PCR)-based 5'-nuclease assay. Fluorescently labeled detection probes anneal to the target DNA. PCR is used to amplify the section of DNA that contains the variant. If the detection probe is an exact match to the target DNA, the 5'-nuclease polymerase degrades the probe, the reporter dye is released from the effects of the quencher dye, and a fluorescent signal is detected. Genotypes are assigned based on the allele-specific fluorescent signals that are detected.(Unpublished Mayo method)

Day(s) Performed

Monday through Friday

Report Available

3 to 8 days

Specimen Retention Time

Whole blood/Saliva swab: 2 weeks; Extracted DNA: 2 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81231-CYP3A5

LOINC Code Information

Test ID Test Order Name Order LOINC Value
3A5Q CYP3A5 Genotype, V 81140-6

 

Result ID Test Result Name Result LOINC Value
610117 CYP3A5 Genotype 81140-6
610118 CYP3A5 Phenotype 79717-5
610119 Interpretation 69047-9
610120 Additional Information 48767-8
610121 Method 85069-3
610122 Disclaimer 62364-5
610123 Reviewed by 18771-6