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Updated: Mar 12, 2026

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
Are you sure the patient is a CYP2D6 ultra-rapid metabolizer?
Keqin Gregg1, Wenjing Guo1, Robert Rhodes1
1Genotox Laboratories, 2170 Woodward Street, Suite 100, Austin, TX 78744, USA.
Aim:
This study investigated the possible cause of false-positive detection of CYP2D6 gene duplication (CYP2D6XN) using the standard TaqMan-based real-time PCR assay from Thermo Fisher Scientific.
Methods:
Used samples of two copy carriers as control to evaluate the effect of sample storage condition and the reference genes with respect to test accuracy.
Results:
The standard test from Thermo Fisher Scientific produced false-positive results of the CYP2D6XN detection when samples were exposed to high temperature and high humidity. The unbalanced template stability between the CYP2D6 testing target and the RNase P reference target was likely the source of error. The problem was reduced but not eliminated when the telomerase reverse transcriptase gene was used as the reference.
Conclusion:
Special care is required in sample handling, testing and data verification to ensure accurate test results and avoid misdiagnosis of an individual as a CYP2D6 ultra-rapid metabolizer.
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