4. How are samples taken? Several methods are used for obtaining samples, including saliva, buccal swab, and peripheral blood. Your patient should not smoke, eat, or drink for at least 30 minutes before providing a saliva sample. For a buccal swab, a cotton swab is rubbed in a circular motion along the oral lining inside each of the patient’s cheeks. The most invasive method is peripheral blood obtained via venipuncture. The sample is sent through expedited mail to an accredited genetic processing laboratory for analysis.
5. How do you interpret the results? Pharmacogenetic testing results are provided in a confidential report. A single gene report allows you to choose psychotropic agents based on pharmacokinetics.5 Some laboratories assess multiple genes in a single report, and create categories of medications (such as “use as directed” or “use with caution”) based on the pharmacodynamic factors of each agent.5,6 Certain laboratories offer dosing guidelines for types of medications that you should use with caution.1,5,6
When interpreting such testing results, it is critical to use your clinical judgment, because pharmacogenetic testing alone does not assess whether a medication will help improve the patient’s symptoms. It is of utmost importance that you have an understanding of pharmacodynamics, knowledge of the patient’s diet and age, and a caring doctor–patient relationship.