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Test ID U1A1V UDP-Glucuronosyl Transferase 1A1 TA Repeat Genotype, UGT1A1


Advisory Information


This test does not detect or report variants other than the *1 (TA6), *28 (TA7), *36 (TA5), and *6 (c.211G->A) alleles. Individuals with a *37 (TA8) allele cannot be distinguished from *28 (TA7) will be assigned *28 (TA7) by this methodology. Numerous variants outside of the TA repeat region have been described that impair UGT1A1 activity. Sequencing of the full gene is also available for detection of variants outside of the TA repeat region.

-Order UGTI / UDP-Glucuronosyl Transferase 1A1 (UGT1A1), Full Gene Sequencing, Irinotecan Hypersensitivity when evaluating risk for irinotecan toxicity.

-Order UGT2 / UDP-Glucuronosyl Transferase 1A1 (UGT1A1), Full Gene Sequencing, Hyperbilirubinemia if evaluation for Gilbert syndrome or Crigler-Najjar syndrome type I or type II is desired.



Specimen Required


Multiple genotype tests can be performed on a single specimen after a single extraction. See Multiple Genotype Test List in Special Instructions 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 specimen in original tube.

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: DNA Saliva Collection Kit (T786)

Container/Tube: Saliva Swab Collection Kit (T786: fees apply)

Specimen Volume: 1 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)/Ambient/Refrigerated


Forms

New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.

Useful For

Identifying individuals who are at increased risk of adverse drug reactions with drugs that are metabolized by UGT1A1; especially irinotecan, but also including atazanavir, nilotinib, pazopanib, and belinostat

 

Identifying individuals with Gilbert syndrome due to the presence of homozygous UGT1A1*6 (c.2111G->A) allele, TA7, homozygous TA8, or compound heterozygous *6, TA7 or TA8

 

Identifying individuals who are carriers of Gilbert syndrome due to the presence of heterozygous TA7 or TA8

Genetics Test Information

This pharmacogenomic test interrogates the thymine-adenine (TA) repeat in the TATA-box of the promoter region of UGT1A1. Repeat number may vary from 5 to 8 TA repeats, with 6 TA repeats representing the most common (normal) number of repeats. Individuals with more than 6 TA repeats may have an increased risk for adverse drug reactions to drugs metabolized by UGT1A1, especially atazanavir, irinotecan, nilotinib, pazopanib, and belinostat. Homozygosity for TA7, TA8, or compound heterozygosity for TA7/TA8 is also consistent with a diagnosis of Gilbert syndrome. Heterozygosity for TA7 or TA8 is consistent with carrier status for Gilbert syndrome. Note that this testing uses a tagging single nucleotide polymorphism (SNP) strategy for the TA5 and for the TA7 and TA8 repeats. This testing is not able to distinguish between TA7 and TA8 so when the tagging SNP is detected, TA7 is assigned. The function of genes with TA7 and TA8 repeats are thought to be the same. In addition, this test evaluates the UGT1A1*6 (c.2111G->A) allele.

Testing Algorithm

See UGT1A1 Test-Ordering Algorithm in Special Instructions.

Method Name

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

Reporting Name

UGT1A1 Genotype

Specimen Type

Varies

Specimen Minimum Volume

Blood: 0.4 mL
Saliva: 1 swab

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday through Friday; 8 a.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81350-UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide AI) (eg, irinotecan metabolism), gene analysis, common variants (eg, *28, *36, *37)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
U1A1V UGT1A1 Genotype In Process

 

Result ID Test Result Name Result LOINC Value
BA0143 UGT1A1 Genotype In Process
BA0144 UGT1A1 Phenotype In Process
BA0145 Interpretation In Process
BA0146 Additional Information In Process
BA0207 Method 49549-9
BA0208 Disclaimer 62364-5
BA0147 Reviewed by In Process