UDP Glucuronosyltransferase 1A1 (UGT1A1) Genotyping

Casandra

Casandra Test Code AR38740Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 0051332CPT Code 81350

UDP Glucuronosyltransferase 1A1 (UGT1A1) Genotyping

Also known as: UGT1A1

Clinical Use

Order Test

Use

The UGT1A1 genotyping test is useful for dosage planning in patients who will receive high-dose irinotecan, as well as in patients with a personal or family history of sensitivity to irinotecan or those who have experienced neutropenia while receiving irinotecan. The test also helps confirm a suspected diagnosis of Gilbert syndrome. UGT1A1 is responsible for the clearance of drugs like irinotecan and endobiotic compounds like bilirubin. Variations in the gene affect transcription efficiency and can lead to irinotecan-related toxicities.

Special Instructions

Patient history form for UGT1A1 sequencing must be submitted with the order, and informed consent for genetic testing is required for patients in New York. Specimen collection should be in lavender (EDTA), pink (K2EDTA), or yellow (ACD solution A or B) tubes and transported refrigerated. Stability is 1 week at room temperature and 1 month refrigerated, while frozen specimens are unacceptable.

Limitations

The test detects variations in the UGT1A1 gene specifically targeted. Variations not targeted will not be detected. The clinical significance of rare alleles such as *36 (TA)5 and *37 (TA)8 in predicting irinotecan toxicities is not well established. Other genetic and non-genetic factors may also contribute to irinotecan toxicity and efficacy. Diagnostic errors can occur due to rare sequence variations.

Test Details

New York Approved