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UDP Glucuronosyltransferase 1A1
|Performed by||Medical Genomics - Molecular Diagnostics|
|In House Availability||Batched assay performed once every 2 weeks|
|Method||PCR and Fragment analysis|
|Collection Instructions||Avoid hemolysis. Due to stability issues these samples should only be collected at UCSF Monday through noon Friday.
Do not collect sample in heparin. Keep sample refrigerated for overnight or longer storage.
For UCSF Samples (from remote sites) Click here for sample collection instructions
For NON-UCSF Samples Click here for Requisition form & Account set-up instructions. Note we only do institutional billing.
|Container type||Lavender top|
|Amount to Collect||3 mL|
|Sample type||EDTA whole blood|
|Preferred volume||3 mL|
|Min. Volume||1 mL|
|UCSF Rejection Criteria||Insufficient sample received.|
|Processing notes||Do not freeze blood. Refrigerate sample if storage is required.
Ship to China Basin Molecular Diagnostics
|Ref Lab Rejection Criteria||Insufficient sample received. Serum, citrated or heparinized plasma received. Samples > 5 days old when received|
(Most common normal allele is 6 repeats (= *1)
|Synonyms||Irenotecan; UGT1A1; UGT 1A1|
|Stability||Refrigerated, 1 month.|
|Turn around times||10-14 days|
|Additional information||An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.
Irinotecan is used for the treatment of metastatic carcinoma of the colon or rectum. It causes severe neutropenia and diarrhea in 20-35% of patients undergoing chemotherapy. The ability to predict toxicity in treated patients is an important consideration.
UGT1A1 catalyzes the inactivation of SN-38, the active and toxic metabolite of irinotecan. The 7TA repeat length polymorphism (termed *28 allele) in the UGT1A1 promoter is associated with decreased UGT1A1 gene expression levels, resulting in lower than normal UGT1A1 enzymatic activity and accumulation of SN-38, the active irinotecan metabolite.
About 15% of North Americans are homozygous for the *28/*28 genotype and thus cancer patients carrying this variant exhibit irinotecan related toxicity and would require lower doses of irinotecan than patients carrying the 6 TA repeat (*1 allele). The clinical significance of the rare 5 and 8 TA repeats, termed *36 and *37 allele, respectively, in predicting irinotecan toxicities is not well established.
|Last Updated||8/21/2014 8:52:48 AM|