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How to Make Sense of Your Pharmacogenomic Test Results

After your saliva sample has been analyzed, your doctor receives a report breaking down your test results. Here are some things you should know about what they’ll see, and how it will pertain to you:

(This post is part of a series explaining pharmacogenomic testing with Prairie, including its benefits and the specific genes that are examined.)

So you’ve sent your saliva sample off to the lab for pharmacogenomic testing. What comes next?

After your DNA has been analyzed, your doctor receives a report with your test results. Here’s what you should know about what they will see, and how it will pertain to you:

What & What Not To Expect From Your Pharmacogenomic Test Results

The goal of pharmacogenomic testing (aka pharmacogenetics or PGx) is to determine how a given individual might respond to certain medications in hopes of providing better treatment. As a result, these tests are primarily concerned with a select group of genes that determines how the body metabolizes certain medications. Because of this, PGx tests are not useful for mapping your family history or predicting if you might be vulnerable to certain diseases.

In addition, don’t expect your test results to directly say which medication will be most effective for you. While the field of pharmacogenomics has incredible potential, there is no widespread scientific evidence supporting the use of genetics in making this type of prediction.

What to ExpectWhat NOT to Expect
Which antidepressants to avoidFamily history
More appropriate starting dosagesDisease susceptibility
How your genes differ from those most commonly studiedThe most effective medication

PGx tests help by telling your provider what medication options could be eliminated or adjusted when formulating a customized treatment plan. For example, while your test cannot conclusively say whether fluoxetine (the generic for Prozac) will help you get better, it might let your doctor know whether the standard dosage is appropriate or whether severe side effects can be expected. This helps your doctor better determine dosage or encourage them to look at different treatment options, both important adjustments to a treatment plan for mental health conditions like anxiety and depression.

Can pharmacogenomic testing help me?

Several research studies have shown potential in PGx testing. One study found a correlation between PGx testing and improvements in those struggling with anxiety and depression. Another stated that conducting PGx testing helped reduce side effects for people with major depressive disorder. The FDA has also supported the use of PGx tests as “companion diagnostics”—supplementing, but not replacing, the prescription guidelines already in place to help your medical provider make an informed decision.

Now that you know what to expect from your test results and how they can help, let’s take a look at an example report so you can better understand what your medical provider sees and how its findings are incorporated into a treatment decision.

What Your Pharmacogenomic Test Looks Like

Let’s look at the above example pharmacogenomic report in more detail and break down its various components.

Your pharmacogenomics test is separated into sections by gene tested. Above is a short excerpt from one of our sample tests measuring the genes CYP2C19, CYP2D6, and CYP3A4. (Read more about these genes along with the other ones examined by PGx tests.)

Result

Each gene has a corresponding numerical label. For example, under the “Result” column, CYP2C19 has the label *1|*17.

This notation has to do with the gene’s haplotype. The word “haplotype” refers to the variants of a gene that are usually linked together. For the sake of simplicity, we’ll just refer to this as a version of a gene.

The number to the right of the vertical line indicates the reference, or most studied (if not most common), version of the gene. In this case, the reference version for the CYP2C19 gene is the *1 type.

The number on the right is the version someone actually has. For example, the person who receives this genetic test will have the *17 version for the CYP2C19 gene.

For the genes we look at, different versions create different enzymes that metabolize drugs differently.

Activity

Under the final column on the right called “Activity”, there is a descriptor for the haplotype’s phenotype. The term phenotype refers to how the enzyme functions as a result of the genetic variation.

For example, if someone has the *17 version of the CYP2C19 gene like above, then they have a Rapid Metabolizer phenotype for that gene. This means that the CYP2C19 enzyme will break down medications at what is considered a faster-than-normal rate.

The other possible phenotypes are Extensive Metabolizer and Slow Metabolizer, and they break down medications at normal and slow speeds, respectively. You can learn more about the genes Prairie examines and their phenotypes in our other blog post.

PhenotypeMetabolism Speed
Rapid MetabolizerFast
Extensive MetabolizerNormal
Slow MetabolizerSlow

Medications

Under every gene heading is a list of medications that are affected by that gene. For example, Citalopram (generic for Celexa) is under the CYP2C19 heading; this means that the enzyme created by this gene is known to metabolize Celexa.

Next to each medication is a recommendation based on the allele a person has. The example we have gives a warning regarding Celexa; because someone with this genetic profile has an Rapid Metabolizer phenotype, the likelihood of a standard Celexa dosage not working for them will be higher. As a result, the test advises that the doctor consider prescribing an alternative antidepressant.

In contrast, our example gives no specific recommendation for the atomoxetine (brand name: Strattera) because someone with this genetic profile will metabolize that medication normally. Thus, if a doctor were to prescribe this medication to someone with this genetic profile, they can comfortably use the standard dosage. 

Conclusion

A PGx test can demystify the prescription process for both provider and patient. The provider gains more insight into how their patient will respond to certain medications and is better prepared to create a customized treatment plan. The patient gains a better understanding of why one medication might be prescribed over another. Because there’s a shared understanding from the PGx report, this helps increase trust between medical provider and patient, which leads to a smoother treatment journey. Other benefits of incorporating PGx testing include reductions in symptoms, healthcare costs, and side effects

If you need anxiety or depression treatment, taking a pharmacogenomic test might help you find a medication that is appropriate for you. If you are interested in learning whether you are likely to benefit from pharmacogenomic testing, Prairie offers a free pharmacogenomics quiz that can let you know if you are especially likely to benefit from PGx testing.

Take Our Free Pharmacogenomics Quiz

Fri Feb 19 2021

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