UGT1A1 Gene Mutation Status (Genetic Test)
This test checks whether you carry a specific genetic variation in the UGT1A1 gene, which may affect how your body processes certain medications or bile acids.
["A genetic test to identify a mutation linked to potential drug interactions or bile flow issues."]
Key facts at a glance
- LOINC
- 93845-6
- Short code
- UGT1A1 allele Geno Bld/T
- Synonyms
- UGT1A1 allele Geno Bld/T
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- molgen
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The UGT1A1 gene helps your body break down medications like certain chemotherapy drugs, pain relievers, and bile acids. This test looks for a common genetic change (UGT1A1*28) that may reduce how well your liver processes these substances, sometimes leading to side effects like nausea or diarrhea.
Why It Might Be Ordered
Your doctor may recommend this test if you’re planning to take medications known to interact with UGT1A1, such as irinotecan (a chemotherapy drug) or certain painkillers, or if you’ve experienced unusual side effects like severe diarrhea or fatigue.
What to Expect Before the Test
No special preparation is needed. A small blood sample will be taken from your arm by a healthcare professional. This test is typically done as part of a genetic screening or before starting certain medications.
What the Results Mean
Results will indicate whether you have the UGT1A1 mutation. If present, your doctor may adjust your medication dose or choose alternatives to minimize side effects. Results are usually available within 1–2 weeks.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The UGT1A1*28 mutation is the most common genetic variant affecting drug metabolism. It can cause conditions like **normal-appearing bilirubin syndrome** (mild jaundice) or increase the risk of severe side effects from drugs metabolized by this enzyme. Doctors use these results to tailor treatment plans and avoid unnecessary risks.
Short name
UGT1A1 Mutation Test
Frequently asked questions
Will this test affect my ability to take certain medications?
How long will I need to wait for my results?
Is this test covered by insurance?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy