Overview: UGT1A1 Polymorphism TestIntroduction: The UGT1A1 Polymorphism Test detects UGT1A1 polymorphisms to assess drug metabolism, preventing toxicity. Following 2023 CPIC guidelines, it uses PCR for high specificity, supporting genetic screening. This test is critical for guiding pharmacotherapy, treatment planning, and improving outcomes in molecular pathology for patients on certain medications like irinotecan.
Other Names: UGT1A1 Genotyping Assay, Gilbert Syndrome Test.
FDA Status: Laboratory-developed test (LDT), meeting molecular pathology standards for diagnostic accuracy.
Historical Milestone: UGT1A1 testing began in the 2000s with pharmacogenomic research. PCR methods improved in the 2010s, enhancing diagnostic precision.
Purpose: Detects UGT1A1 polymorphisms to assess drug metabolism, guides dosing, and prevents toxicity.
Test Parameters: 1. UGT1A1 TA Repeats 2. Polymorphism Status
Pretest Condition: No fasting required. Collect whole blood, buccal swab, or saliva. Report history of drug toxicity or Gilbert syndrome.
Specimen: Whole Blood (EDTA, 2-5 mL), Buccal Swab (sterile swab, 1-2 swabs), Saliva (sterile container, 1-2 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: Not frozen
Medical History: Document drug toxicity, jaundice, or history of Gilbert syndrome. Include current medications, especially chemotherapy agents.
Consent: Written consent required, detailing the tests purpose, drug metabolism implications, and risks of sample collection.
Procedural Considerations: Uses PCR to detect UGT1A1 polymorphisms (e.g., TA repeats). Results are available in 3-5 days, supporting clinical decisions. Performed in laboratories, often for pharmacogenomic screening.
Factors Affecting Result Accuracy: Low DNA yield or contamination can affect results. Sample quality impacts specificity.
Clinical Significance: UGT1A1 polymorphisms (e.g.,
28/28) predict poor drug metabolism, guiding dose adjustments for drugs like irinotecan. Normal genotypes suggest standard dosing.
Specialist Consultation: Consult a pharmacologist or oncologist for result interpretation and treatment planning.
Additional Supporting Tests: Liver function tests, bilirubin levels, or genetic counseling to assess drug metabolism risks.
Test Limitations: Specific to UGT1A1-related drugs; other metabolic pathways may be missed. Sample quality affects sensitivity.
References: CPIC Pharmacogenomics Guidelines, 2023; Clinical Pharmacology & Therapeutics, Innocenti F, 2022.
