Although genetic testing is becoming an increasingly common medical practice, many people are still unfamiliar with how these types of tests work, what they are used for, and what their advantages and disadvantages may be. Read on to get some answers to your frequently asked questions about genetic testing.
What is genetic testing?
Simply put, genetic testing is the process of examining your genes using laboratory methods. Genes contain the DNA instructions you have inherited from your parents; looking at this information can provide important insights into your health.
What is genetic testing used for?
Depending on the type of test, genetic testing can have many different purposes. A genetic test can help to diagnose a disease; identify what gene changes caused a disease that has already been diagnosed; determine how severe or serious a disease may be for a particular individual; provide information that doctors can use to decide what medicine or treatment may be best for certain patients; identify a person’s level of risk for developing a particular disease; identify gene changes that parents may pass on to children; and to screen newborns and infants for certain conditions that may be treatable if detected early.
What types of genetic tests are there?
There are a number of different types of genetic tests, each used to gather different kinds of information about a particular person and his or her health.
Diagnostic tests: These tests are used to determine what disease is making you sick or causing your symptoms; they are especially useful when conventional testing methods aren’t able to establish what the problem is. For example, people with celiac disease may experience symptoms that mimic other health conditions like irritable bowel syndrome, making the disease very difficult to diagnose. A diagnostic genetic test, however, can identify the presence of celiac disease, and therefore allow a patient to make better-informed decisions and choices about how to manage the condition.
Predictive and pre-symptomatic tests: As their names suggest, rather than being administered after you already have a disease, these types of tests are administered beforehand in order to determine how likely it is that you will be affected by a particular disease. The information provided by predictive tests can influence decisions you make about your lifestyle and healthcare.
Carrier tests: Some people have a change within one of their genes that has been linked to a particular disease; these individuals are said to be “carriers” of that disease, even if they do not develop it. The risk of being a carrier, of course, is that you may pass on the gene change to your children, who could develop the associated disease or become carriers in their turn. Carrier tests are used to find the carriers of these specific changes; for the most part, carrier tests are offered to people with a family history of a particular inherited disease.
Prenatal tests: These tests are performed during pregnancy to help establish if a developing fetus has or is at risk for certain diseases.
Newborn screening: These tests are performed on babies within the first few days after birth to provide an early diagnosis of conditions that are associated with early health and development problems.
Pharmacogenomic tests: Because not everyone’s body is able to process drugs and medicines in the same way, pharmacogenetic tests can help identify whether someone is likely to have an adverse response to certain kinds of medication.
Research genetic tests: Performed for research purposes, these tests are not necessarily intended to benefit a specific patient, but rather to contribute to our general body of knowledge about health and diseases.
What benefits and drawbacks are associated with genetic testing?
Benefits: Whether or not a genetic test identifies a particular mutation or change, the process of being tested can help remove uncertainty surrounding a patient’s health. Genetic test results may help doctors make better recommendations for treatment or monitoring of a particular condition, and may enable individuals to make lifestyle changes that will lower their risk of developing a certain disease.
Drawbacks: Learning and processing the results of a genetic test can be an emotionally challenging experience. Some people also find it hard to deal with the limitations and ambiguities of genetic testing. For example, a positive result from a genetic test does not mean that you will necessarily develop a disease, and it’s also not always certain what types of symptoms you may have or how severe they will be. There is also the financial aspect to consider: genetic tests can range in cost from $100 to upwards of $2,000, and insurance coverage of such tests may vary.
How do I decide whether or not to get a genetic test?
Genetic testing is a voluntary process, and there are many reasons why you may or may not choose to get tested. If your family has a certain pattern of disease, for example, your doctor may suggest a genetic test. In addition, you may wish to have more certainty about some health information if you are planning to have a child. To help make your decision, it can be useful to discuss the process with a genetic counselor, who can guide you through the advantages and limitations of the test you are considering, and help you understand your test results.