Predictive testing

Predictive Testing vs. Diagnostic Testing:
Predictive testing is used to search for genetic mutations linked with a condition before you show symptoms. Diagnostic testing is used to find out if you have a condition associated with symptoms you already have.

The Genetic Testing Stories monograph is a collection of real stories from people who had all different types of genetic testing, including predictive testing.

If you think you need predictive testing, find a genetic counselor in your area to help you make the decision.

What Is Predictive Genetic Testing

Predictive genetic testing searches for genetic changes, or mutations, that are linked to disease. These tests are done before you show any signs of a disease. Predictive testing may be useful to people who:

  • Have a family history of a treatable genetic disorder, AND
  • Show no signs of illness.

 

Testing Process

You can get a predictive ge

netic test from healthcare providers or direct-to-consumer companies. A health professional should review your results with you to make sure you understand your options. The results from a predictive test may affect:

  1. Your life plan
  2. Your health choices
  3. Your mental and emotional state

Test results also may show information about your relatives. Carefully think about your results and the effect they can have on family members. You can find more information about the testing process on the genetic testing page.

 

Testing Types and Results

There are two different types of predictive genetic testing:

  1. Presymptomatic Testing: Positive tests results show that you will develop symptoms of a disease. For example, this type of test is used to check for mutations linked to Huntington’s Disease.
  2. Predispositional Testing: Positive tests results show that you are more likely than others to develop symptoms of a disease. But, doctors cannot know for sure if you will get sick. For example, this type of test is used to check for mutations linked to breast cancer.

Many laboratories will not do a predictive genetic test until certain things have been explained to you. This may include information about the test that you are getting and what the results mean. You also may need to sign a consent form and agree to get advice from a health professional about your results.

Most predictive tests have some uncertainty about:

  • If a condition will develop,
  • When it might develop, and
  • How sick you will get.  

Your next steps will depend on the type of test you took. With a positive presymptomatic test result, get ready for symptoms in the future. With a positive predispositional test result, think about what you can do to avoid disease. In both cases, talk to a healthcare professional.

Many laboratories will not do a predictive genetic test until certain things have been explained to you. This may include information about the test that you are getting and what the results mean. You also may need to sign a consent form and agree to get advice from a health professional about your results.