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HelpTest Code LAB9772 UGT1A1 Genotyping for Irinotecan Toxicity
Methodology
Polymerase Chain Reaction (PCR) amplification of the promoter of UGT1A1 promoter and Capillary Electrophoresis. Specific single-base variation in UGT1A1 with effects on irinotecan toxicity (including *6 and *93) are not detected by this assay.
Performing Laboratory
Barnes-Jewish Hospital Molecular Diagnostics Laboratory (BJH MDL)
Specimen Requirements
Form: Molecular Diagnostics Requisition
Specimen Type: Whole blood
Container/Tube: Lavender top (EDTA)
Specimen Volume: Full tube
Specimen Minimum Volume: 1-2 mL
Collection Instructions: Invert several times to mix blood. Clotted blood is not acceptable.
Pediatric collection volume: 2.0 mL - minimum 1.0 mL
Specimen Transport Temperature
Ambient/Refrigerate/Frozen NO
Reference Values
Alleles detected:
(TA)5 = UGT1A1*36
(TA)6 = UGT1A1*1
(TA)7 = UGT1A1*28
(TA)8 = UGT1A1*37
(TA)6/6: Normal Metabolizer; standard risk of toxicity from irinotecan may be expected.
(TA)6/7: Intermediate Metabolizer; dose reduction or modification should be considered per FDA labeling.
(TA)7/7: Poor Metabolizer; dose reduction or modification should be considered per FDA labeling.
All other genotypes: Inconclusive; insufficient information currently available from clinical studies and professional guidelines to assess the risk of toxicity of irinotecan therapy.
An interpretive report will be provided.
Literature Reference:
Innocenti F, Undevia SD, Lyer L, et al. Genetic variants in the UDP-glucuronasyltransferase 1A1 gene predict the risk of severe neutropenia of irinotecan. J Clin Oncol 2004;22(8):1382-88.
Day(s) Test Set Up
Friday
Turnaround Time:
STAT: not available
Routine: 2 to 7 business days
Test Classification and CPT Coding
81350
Additional Information
For BJH Laboratory Use Only
Analyte Stability:
Blood is stable 0 to 4 hours at ambient temperature, up to 168 hours refrigerated.
Laboratory Processing Instructions:
Test performed in BJH MDL