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PGx Testing

A Pharmacogenomics (PGx) test is a type of genetic test that analyzes how a person's genetic makeup affects their response to medication.

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This test is becoming increasingly popular as it can help healthcare providers personalize medication regimens for their patients, reducing adverse drug reactions and improving patient outcomes. In this blog post, we will discuss how to read a PGx test in lay terms, including the genetic variations and their impact on drug metabolism.

What is a PGx Test?

A PGx test is a genetic test that analyzes variations in genes that are involved in drug metabolism. These genes play a crucial role in determining how a person's body processes medication, including how quickly the medication is broken down and eliminated from the body. By analyzing these genetic variations, healthcare providers can gain insight into how a patient may respond to certain medications and adjust their treatment plan accordingly.

How to Read a PGx Test

A PGx test typically provides information on specific genetic variations in a patient's DNA that can affect drug metabolism. The results of the test are often presented in the form of a report, which can be complex and difficult to understand for patients and healthcare providers alike. Here are some key elements to look for when reading a PGx test:

  1. Genetic Variations

The first thing to look for in a PGx test report is the genetic variations that have been analyzed. This information is typically presented as a list of specific genes and their corresponding variations. Some common genes that are analyzed in a PGx test include CYP2D6, CYP2C19, CYP2C9, and VKORC1.

  1. Phenotypes

Phenotypes refer to the observable characteristics of an individual resulting from the interaction of their genetic makeup with their environment. In a PGx test report, phenotypes are often used to describe how a patient may metabolize certain drugs based on their genetic variations. For example, a patient may be classified as a "poor metabolizer" if they have genetic variations that reduce the activity of a particular enzyme, resulting in slower drug metabolism and potentially higher drug concentrations in the body.

  1. Medications

PGx tests can provide information on how a patient's genetic variations may impact their response to specific medications. The report may list medications that are affected by the patient's genetic variations, including information on how the patient is likely to respond to these medications based on their phenotype.

  1. Recommendations

Based on the results of the PGx test, healthcare providers may make recommendations for medication dosing, drug selection, or monitoring based on a patient's genetic variations. These recommendations are often based on guidelines established by professional organizations such as the Clinical Pharmacogenetics Implementation Consortium (CPIC) or the Dutch Pharmacogenetics Working Group (DPWG).


  1. Clinical Pharmacogenetics Implementation Consortium. (2021). CPIC Guidelines. Retrieved from
  2. Dutch Pharmacogenetics Working Group. (2021). DPWG Guidelines. Retrieved from
  3. National Institutes of Health. (2020). Pharmacogenomics Fact Sheet. Retrieved from
  4. Shuldiner, A. R., Relling, M. V., & Peterson, J. F. (2013). Pharmacogenomics. New England Journal of Medicine, 369(10), 921-929. doi: 10.1056/NEJMra1207677
  5. Swen, J. J., Wilting, I., de Goede, A. L., Grandia, L., Mulder, H., Touw, D. J., . . . Guchelaar, H. J. (2011). Pharmacogenetics: from bench to byte--an update of guidelines. Clinical Pharmacology and Therapeutics, 89(5), 662-673. doi: 10.1038/clpt.2011.34
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Dr. Sue Ojageer

Dr. Sue Ojageer is a licensed pharmacist with over 15 years' experience. She is dedicated to providing exceptional pharmaceutical care to her patients. Dr. Ojageer received her Doctorate of Pharmacy (PharmD) from St. John's University.

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