Information on Requesting Pharmacogenetic Testing
Our pharmacogenetics laboratory offers genotyping of pharmacogenetically relevant genes involved, among other processes, in the enzymatic biotransformation of drugs and in other processes relevant to drug efficacy and tolerability. These include CYP2C19, CYP2D6 and APOE. The results may provide information on genetically determined differences in drug response and tolerability and support individualised treatment planning.
Why is genotyping useful?
CYP2D6 and CYP2C19 encode enzymes involved in the metabolism of many medications. Depending on enzyme activity, which may be influenced by genetic variants, drugs can be metabolised at different rates, ranging from slow to ultrarapid. Determining the individual's genetic profile can therefore provide information about their metabolic capacity. This information may help guide dosage adjustments and reduce the risk of adverse effects or insufficient therapeutic efficacy. In this way, treatment outcomes may be improved.
APOE is of particular relevance for certain anti-amyloid antibody therapies used to treat Alzheimer's disease, as the APOE ε4 allele, especially in individuals with the homozygous APOE ε4/ε4 genotype, is associated with an increased risk of adverse effects.
Drugs associated with CYP2D6
Amphetamine, amitriptyline, aripiprazole, atomoxetine, brexpiprazole, clomipramine, clozapine, codeine, desipramine, dexamfetamine, doxepin, fluoxetine, flupentixol, fluphenazine, fluvoxamine, haloperidol, imipramine, maprotiline, metoclopramide, nortriptyline, opipramol, paroxetine, perphenazine, pimozide, promethazine, tamoxifen, torasemide, trimipramine, venlafaxine, vortioxetine, zuclopenthixol.
Drugs associated with CYP2C19
Amitriptyline, atomoxetine, brivaracetam, citalopram, clomipramine, clobazam, clopidogrel, clozapine, diazepam, doxepin, escitalopram, fluoxetine, imipramine, pantoprazole, perazine, sertraline, trimipramine, venlafaxine, voriconazole.
Drugs associated with APOE
Lecanemab, Donanemab
What should be considered when requesting genotyping?
In addition to the completed request form, we require a blood sample. Blood should be collected into a 2.7 mL EDTA whole-blood Monovette without additives. Please follow the instructions for proper transport and shipping, as the quality of genotyping and result interpretation depends to a considerable extent on the careful and complete collection of all required information.
Transport and shipping
The EDTA whole-blood Monovette must be labelled with the patient's name and the date and time of blood collection. The sample must then be transported together with the fully completed request form to the Pharmacogenetics Laboratory of the Centre of Mental Health (ZEP) at Würzburg University Hospital.
Samples must be shipped in containers for diagnostic specimens that comply with DIN EN 829. Shipping must comply with the applicable dangerous goods regulations for Biological Substance, Category B (formerly referred to as “Diagnostic Specimen”), in accordance with Packing Instruction P650.
Shipping address:
Universitätsklinikum Würzburg
ZEP /PG-Labor
Margarete-Höppel-Platz 1
97080 Würzburg
Germany
The sender is responsible for ensuring compliance with all applicable shipping regulations.
Storage
If the sample cannot be transported to the Pharmacogenetics Laboratory within 90 minutes, it must be stored in a refrigerator at 4°C until shipment. If storage exceeds two weeks, the sample must be frozen at −20°C. Refrigeration is not required during transport.
Information required on the request form
For samples submitted by external institutions, a separate request form must be completed for each test. The form also serves as a documentation sheet. All relevant information must be recorded, including:
- Full name, address and contact details of the requesting institution
- Patient's surname, first name, date of birth and sex
- Diagnosis
- Date and time of blood collection and sample volume. EDTA whole-blood Monovettes containing 2.7 mL of blood and no additives must be used.
- Names and daily doses of all medications
- Adverse effects associated with medication.
For samples submitted internally within the University Hospital of Würzburg, the request is generated electronically via the laboratory information system LAURIS, following the same procedure as for the paper request form.
Reporting of results
Our aim is to report the results of pharmacogenetic testing within five to ten working days of receipt of the sample in the Pharmacogenetics Laboratory.
The report specifies the identified genotype and/or haplotype and, where this can be determined for the gene tested, the resulting functional consequence and/or phenotype. Where scientifically established associations are available, the results may support recommendations for dose adjustment or changes to medication.
Results are sent by post for external requests and via the internal hospital mail system for requests originating within the hospital.
Any relevant circumstances affecting the analysis, such as the condition of the sample, as well as clinically relevant information, are documented to support interpretation.
The staff of the Pharmacogenetics Laboratory will be happy to answer any questions. If necessary, specific questions regarding further treatment decisions will be assessed by a member of the clinical team with relevant expertise.
Costs and billing
According to the German fee schedule (DKGNT), the following GOÄ billing codes apply:
- For CYP2D6 and CYP2C19: GOÄ codes 3920, 3922 and 3924 for each gene.
- For APOE: GOÄ codes 3920 and 3922.
For billing of externally submitted samples, please contact us by telephone in advance.
Telephone: +49 931 201-77260 or +49 931 201-76403
Quality assurance
The in-house method used for pharmacogenetic testing of CYP2D6 and CYP2C19 meets the basic safety and performance requirements set out in Annex I of Regulation (EU) 2017/746 of the European Parliament and of the Council of 5 April 2017 on in vitro diagnostic medical devices, repealing Directive 98/79/EC and Commission Decision 2010/227/EU.
For APOE genotyping, the laboratory uses the commercially available gb GENETIC APOE assay manufactured by Generi Biotech s.r.o. (Czech Republic). This CE-marked in vitro diagnostic assay is certified in accordance with Regulation (EU) 2017/746 (IVDR) and is intended for the qualitative genotyping of the APOE polymorphisms rs429358 and rs7412.
The in-house methods for CYP2D6 and CYP2C19 are used exclusively at:
Universitätsklinikum Würzburg
Labor für Pharmakogenetik des Zentrums für Psychische Gesundheit (ZEP)
Klinik und Poliklinik für Psychiatrie, Psychosomatik und Psychotherapie
Margarete-Höppel-Platz 1
97080 Würzburg
Germany
Contact
Dr. med.
Bodo Warrings (Management)
Head of the TDM/PGx laboratory and senior physician
+49 931 201-77810
PD Dr. rer. nat.
Maike Scherf-Clavel
Head of the personalized pharmacotherapy working group
+49 931 201-77260
Contact
Appointment
Policlinic
Phone: + 49 931 201-77800
E-Mail: ep_poli@ukw.de
In-patient care
Phone: +49 931 201-76050
E-Mail: ep_poli@ukw.de
Address
Klinik und Poliklinik für Psychiatrie, Psychosomatik und Psychotherapie des Universitätsklinikums | Margarete-Höppel-Platz 1 | 97080 Würzburg | Deutschland