Pharmacogenetic Tests

What is pharmacogenetic testing?

Pharmacogenetics, also called pharmacogenomics, is the study of how genes affect the body's response to certain medicines. Genes are parts of DNA passed down from your mother and father. They carry information that determines your unique traits, such as height and eye color. Your genes can also affect how safe and effective a particular drug could be for you.

Genes can be the reason the same medicine at the same dose will affect people in very different ways. Genes may also be the reason some people have bad side effects to a medicine, while others have none.

Pharmacogenetic testing looks at specific genes to help figure out the types of medicines and dosages that may be right for you.

Other names: pharmacogenomics, pharmacogenomic testing

What is it used for?

Pharmacogenetic testing may be used to:

Find out whether a certain medicine could be effective for you
Find out what the best dosage might be for you
Predict whether you will have a serious side effect from a medicine

Why do I need pharmacogenetic testing?

Your health care provider may order these tests before you start a certain medicine, or if you are taking a medicine that is not working and/or causing bad side effects.

Pharmacogenetic tests are only available for a limited number of medicines. Below are some of the medicines and genes that can be tested. (Gene names are usually given in letters and numbers.)

Medicine	Genes
Warfarin: a blood thinner	CYP2C9 and VKORC1
Plavix, a blood thinner	CYP2C19
Antidepressants, epilepsy medicines	CYP2D6, CYPD6 CYP2C9, CYP1A2, SLC6A4, HTR2A/C
Tamoxifen, a treatment for breast cancer	CYPD6
Antipsychotics	DRD3, CYP2D6, CYP2C19, CYP1A2
Treatments for attention deficit disorder	D4D4
Carbamazepine, a treatment for epilepsy	HLA-B*1502
Abacavir, a treatment for HIV	HLA-B*5701
Opioids	OPRM1
Statins, medicines that treat high cholesterol	SLCO1B1
Treatments for childhood leukemiaand certain autoimmune disorders	TMPT

What happens during a pharmacogenetic test?

Testing is usually done on blood or saliva.

For a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a saliva test, ask your health care provider for instructions on how to provide your sample.

Will I need to do anything to prepare for the test?

You usually don't need any special preparations for a blood test. If you are getting a saliva test, you should not eat, drink, or smoke for 30 minutes before the test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

There is no risk to having a saliva test.

What do the results mean?

If you were tested before starting a treatment, the test can show whether a medicine will likely be effective and/or if you are at risk for serious side effects. Some tests, such as the ones for certain drugs that treat epilepsy and HIV, can show whether you are at risk for life-threatening side effects. If so, your provider will try to find an alternate treatment.

Tests that happen before and while you're on treatment can help your health care provider figure out the right dose.

If you have questions about your results, talk to your health care provider.

Is there anything else I need to know about pharmacogenetic testing?

Pharmacogenetic testing is only used to find out a person's response to a specific medicine. It is not the same thing as genetic testing. Most genetic tests are used to help diagnose diseases or potential risk of disease, identify a family relationship, or identify someone in a criminal investigation.

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