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Test Code TPNUQ Thiopurine Methyltransferase (TPMT) and Nudix Hydrolase (NUDT15) Genotyping, Varies


Ordering Guidance


For thiopurine methyltransferase (TPMT) enzyme activity testing, order TPMT3 / Thiopurine Methyltransferase Activity Profile, Erythrocytes; however, this test should also be ordered because TPMT enzyme activity testing cannot detect variants in NUDT15, which also impact thiopurine metabolism.



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) 9 days/Refrigerated 30 days

 

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: 1 Swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient 30 days

 

Specimen Type: Extracted DNA

Container/Tube: 2-mL screw top tube

Specimen Volume: 100 mcL

Collection Instructions:

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

2. Provide concentration of DNA and volume on tube.

Specimen Stability Information: Frozen (preferred)/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)

-Gastroenterology and Hepatology Test Request (T728)

-Therapeutics Test Request (T831)

Useful For

Predicting potential for toxicity to thiopurine drugs (6-mercaptopurine, 6-thioguanine, and azathioprine)

Method Name

Real-Time Polymerase Chain Reaction (PCR) With Allelic Discrimination Analysis

Reporting Name

TPMT and NUDT15 Genotype, V

Specimen Type

Varies

Specimen Minimum Volume

Blood: 0.4 mL
Saliva, extracted DNA: see Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
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 TPMT genotype, with associated star alleles, is assigned using standard allelic nomenclature as published by the TPMT Nomenclature Committee.(1) NUDT15 genotype and associated star alleles are as described by Moriyama et al.(2) and catalogued in the Pharmacogene Variation Consortium (www.pharmvar.org).

 

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

Day(s) Performed

Monday through Friday

Report Available

2 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

0034U

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TPNUQ TPMT and NUDT15 Genotype, V 93193-1

 

Result ID Test Result Name Result LOINC Value
610159 TPMT Genotype 41048-0
610160 TPMT Phenotype 79713-4
610161 NUDT15 Genotype 93194-9
610162 NUDT15 Phenotype 93195-6
610163 Interpretation 69047-9
610164 Additional Information 48767-8
610165 Method 85069-3
610166 Disclaimer 62364-5
610167 Reviewed by 18771-6