Clinical Genetic Testing
Does this test have other names?
Genetic screening, DNA test or testing, chromosomal test, gene testing, DNA-based
What is this test?
Genetic testing is usually done to screen newborns, children, or adults for inherited
diseases or genes that put them at increased risk for a certain disease. Some parents
choose to be screened before or during pregnancy to see whether they are carriers
of a certain disease, such as hemophilia.
Your genes are like a road map: They hold the blueprint for all your inherited traits,
from the color of your eyes to how tall you will grow.
But your genes can also tell you whether you're at risk of inheriting a disease, such
as breast cancer, cystic fibrosis or Huntington disease. They can even help tell your
healthcare provider how to tailor the right medicines for your condition.
A genetics test can find out whether you have damaged, missing, or overactive genes
that can cause certain diseases. This test scans the pattern of your genes, or DNA,
in your blood or other fluids, such as saliva or urine.
These are types of genetic testing:
Gene tests, which examine individual genes or fairly short strands of DNA or RNA
Chromosomal tests, which test entire chromosomes or long strands of DNA
Biochemical tests, which look at protein and enzyme activities
Why do I need this test?
You may need this test, even if you don't have symptoms, if your healthcare provider
suspects you have inherited a certain condition. This test can also find out whether
your biological child might have inherited a disorder from you or the other biological
If you belong to an ethnic or other group in which a certain inherited disease is
more common, your healthcare provider may order a test to help determine your risk.
Your healthcare provider may also order a test if you have a disease that runs in
Genetic testing is used in the following ways:
To help your healthcare provider find out the cause of your disease or disorder
To find out whether you are a carrier of a gene for a disease before or after you
To aid parents in finding out whether an unborn child has a gene for a disease
To help parents find out whether their newborn baby has a damaged gene that can cause
To help determine your risk for a certain disease
To help your healthcare provider find out which medicine or therapy might be best
Genetic testing can ease your mind about your or your child's inherited risk for a
certain disease if you get a negative result. Finding out you are predisposed to developing
a certain disease could lead to your getting more regular screenings or making lifestyle
changes to help prevent the disease. Even learning that you have an inherited disease,
painful as the news may be, can help you plan treatment and take other important steps.
In some cases, though, positive findings might force you to make some unwelcome choices,
so it is your right to choose or turn down genetic testing.
What other tests might I have along with this test?
If you or your newborn has symptoms of a particular disease, your healthcare provider
will likely run specific tests for that disease.
Before you go through any genetic test, your healthcare provider will ask you to get
pretest counseling so that you can understand what the test involves, how accurate
it is, how you will get the results, and how results will be shared with your healthcare
provider. You may also want to ask about emotional and psychological support.
What do my test results mean?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
If your healthcare provider is looking for a particular gene, your results will be
either negative or positive for that gene. Even if you were born with a gene that
puts you at risk for a disease, it doesn't necessarily mean you will ever have it.
The findings from a genetic test may not be simple to understand. Your healthcare
provider may refer you to a genetic counselor, who can represent your interests and
help translate the results for you.
Genetic counselors can help you understand the science behind genetic testing and
the emotional response you may have to the findings. They can also help research your
family history and look at your medical records.
How is this test done?
This test can be done on samples of your skin, blood, hair, urine, or other tissues.
You might be asked to give a blood sample or a swab from the inside of your mouth.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
Although this test poses no major physical risks, it can affect your emotions, your
job, and even your healthcare coverage. The Genetic Information Nondiscrimination
Act was passed in 2008 to protect insurers and employers from using the results of
genetic testing to drop your healthcare coverage or to fire you.
Consumers can get genetic testing done with kits that are available on the Internet.
This can be a risky move, however. Different laboratories can have results that are
difficult to understand, and the results can vary. Healthcare providers caution against
getting tested without speaking with a genetic counselor first.
Because of the emotional impact of genetic testing, you may want to consider how you
will feel if you find out that you or someone you love has a gene that can cause a
physical disorder or disease. This may be especially true for a disease such as Alzheimer,
which has no known prevention or cure.
What might affect my test results?
Different kinds of genetic tests yield different information, and results may vary
by laboratory. Your results are based on a test of your genes, so lifestyle choices
will not affect the findings.
How do I get ready for this test?
You don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you are taking. This includes medicines
that don't need a prescription and any illicit drugs you may use.