UDP-Glucuronosyltransferase 1A1 (UGT1A1) Gene Mutation Screening (Qualitative)
This test checks for specific genetic variations in the UGT1A1 gene, which may affect how your body processes certain medications or contribute to conditions like Gilbert’s syndrome or certain cancers.
["A simple blood test to identify potential genetic differences that could influence drug metabolism or health risks."]
Key facts at a glance
- LOINC
- 104285-2
- Short code
- UGT1A1 gene.p.G71R Bld/T Ql
- Synonyms
- UGT1A1 gene.p.G71R Bld/T Ql
- 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
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have a family history of conditions linked to UGT1A1 mutations, such as hereditary hemochromatosis, certain cancers, or severe reactions to medications like irinotecan (a chemotherapy drug). It may also be used before starting certain medications that rely on this enzyme for metabolism.
How the Test Works
Blood is drawn to analyze DNA for known mutations in the UGT1A1 gene. The test is qualitative, meaning it only indicates whether the mutation is present or not, rather than measuring its exact quantity.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your provider specifies it. Wear comfortable clothing and plan to stay for the procedure.
What to Expect During the Test
A healthcare provider will insert a needle into your arm to collect a small amount of blood. You may feel a brief pinch, but it’s usually over quickly. The blood sample is then sent to a lab for genetic analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
UGT1A1 mutations can lead to reduced enzyme activity, which may cause side effects from medications or increase the risk of certain cancers (e.g., colorectal cancer). For example, the *UGT1A1*26 allele is linked to higher irinotecan toxicity. Identifying these mutations helps tailor treatment plans to avoid adverse reactions.
Short name
UGT1A1 Gene Mutation Test
Frequently asked questions
What does a positive result mean?
Will this test affect my medication?
Can this test be done at home?
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