Frequent Questions
The Genetic Pharmacology Service for children and adults at Cincinnati Children's Hospital Medical Center provides answers to frequent questions about pharmacogenetic testing.
Why is a pharmacogenetic (PG) test done?
A pharmacogenetic (PG) test can be done before or after a medicine is given.
Before a medicine is given, a PG test is done to select a medicine and dose that will work best for you and cause the fewest unpleasant side effects.
After a medicine is given, a PG test is done to help us understand why you are having problems with a medicine. The test may also help us decide if you would benefit from a different dose or different medicine.
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Is PG testing required?
No. The test is optional. You can be treated with standard medicine doses without this gene testing.
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What is being tested with a PG test?
A small sample of blood or scrapings from the inside of your cheek is analyzed for specific genes that can influence a person's response to a medication.
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What are genes?
Genes are segments of DNA inherited from biologic parents. Most of our genes exist in pairs, one inherited from each parent. Genes act as instructions to make molecules called proteins.
Most genes are the same in all people, but some genes are slightly different between people. Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each person's unique physical features.
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What do genes have to do with medicines?
Some genes affect the way medicines work in the body. When comparing a group of people, there can be slight differences in each gene's structure. These differences can affect how people react to medicine.
- Some gene differences might make it harder for the body to get rid of some medicines. Usual doses of such medicines could give some people unexpected side effects.
- Some gene differences can cause the body to use up a medicine too fast. Normal doses of such a medicine won't work as well and the person may need higher doses.
- Some gene differences prevent the medicine from having its intended effect. A different medicine may have to be considered.
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How will the PG test help me?
- The test may improve the chances that the medicine will help you as intended.
- The test may lower the chance of unpleasant side effects from the medicine.
- The PG test for the medicine may only need to be done once in a lifetime. The test looks at common gene differences. If the common gene differences are found in your blood, then the test will not need to be repeated. However, if common gene differences are not found, it is possible that the test will be repeated when improved technology allows the laboratory to analyze samples for many more differences in the gene.
- The gene tested today may be important for medicines that you need in the future.
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Does the PG test have any limitations?
- Yes, as do many types of tests.
- In the case of the PG test, it only analyzes common gene differences. This means if the test does not find any of the common gene differences, you could still have one or more rare gene differences. The test will not detect rare gene differences. Some of these rare differences might affect how you react to the medicine.
- Gene differences are only one of many factors that can affect how you react to medicine. A few examples of other factors are your age, weight, other illnesses, lifestyle and environment. These factors need to be considered along with the PG test results.
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Is there anything else I should know about the PG test?
In the future, some of these common gene differences may be found to be associated with other medical conditions.
The test results may be important for other family members. Biologic brothers, sisters and parents may have one or more of the same tested genes in common.
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How much does the PG test cost?
The cost of the PG test depends on many factors. Insurance companies usually cover the costs of genetic tests that are used to guide medical management. Because insurance companies vary in their coverage policies, it is always prudent to ask them directly whether or not they will cover the cost of PG testing.
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How long does it take to get the test results?
Test results will be ready in two business days.
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How will I learn about my test results?
Your physician will receive a report from the laboratory and discuss the results and their implications with you.
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Will my gene result be in the medical records?
No. The laboratory realizes some people worry that insurance companies or employers will use genetic information to discriminate against them. The tested gene result will be stored in a safeguarded database in the Cincinnati Children's Molecular Genetics Laboratory. Patients may have the gene result. Cincinnati Children's strictly follows HIPAA guidelines to protect medical information.
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What will happen to my sample?
Your DNA from the blood sample may be stored for up to two years in case future tests are needed. Neither your sample nor DNA will be used for research purposes.
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Información Para el Paciente / Los Padres |
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Will I receive any type of handout or educational material?
Patients and parents of pediatric patients should be given a choice whether or not to have a pharmacogenetic test. The downloadable handout below will help you decide whether or not to have testing by providing answers to frequently asked questions:
Download the Gene Test for Medicines: Patient / Parent Information handout (90k) in portable document format (.pdf).
You must have Adobe Acrobat" Reader installed on your computer to read this file. You can download Adobe Acrobat" Reader at Adobe's Web site by selecting the version appropriate for your type of computer.
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