False Positive and Negative Carrier Testing Results

Everyone carries different information in their genes. Genetic mutations are the reason that human beings differ in appearance, personality, and often health outcomes. When a person inherits a particular genetic mutation for a genetic disorder from their parents at conception, they can either be affected by the disorder, or they can be a carrier for it. (depending on the type of inheritance). This information can be passed down to any offspring.

As time and technology progresses, researchers and scientists have gained more knowledge about what makes up a person, their DNA, as well as what causes different variations in people and genetic conditions. Couples interested in starting a family are increasingly being recommended carrier screening to assess their probability of having a child who is born with a genetic disorder. But what if the results aren’t accurate?

Carrier Screening

Genetic carrier screening can give you and your partner more information about whether you carry a genetic mutation, which genetic mutations you carry, and how likely it will be that you pass on any particular mutation to your offspring. The process involves a blood draw from both parents to test for over 110 hereditary disorders. Your results will be shared with you by your doctor and there are three potential outcomes: a positive result, a negative result, and an inconclusive result.

False Positives and Inconclusive Results

If you receive a positive result, this means that the carrier screening has identified a genetic mutation that could cause a certain genetic disorder. An inconclusive result means that the screening was not able to determine whether or not you carry that potential mutation. If you receive a positive or inconclusive result on a carrier screening, you will be referred by your doctor to a specialist called a genetic counselor. They will be able to discuss any further testing options and potential next steps to plan for a family.

A false positive result occurs when you do not actually have the genetic mutation that you tested positive for. This can often lead to undue panic for the couple, and potentially unnecessary funds wasted on additional testing and fertility options.

False Negatives

If you receive a negative result, this means that the carrier screening has not identified a genetic mutation that can lead to a certain genetic disorder. Couples who receive a negative carrier screening result will usually go on to conceive and start their family as planned.

A false negative result occurs when you do have the genetic mutation you were tested for, but the carrier screening shows that you do not. This can lead to a child being born with a genetic disorder even though both parents tested negative as carriers.

Speaking with a Genetic Counselor

Most babies are born without a serious genetic condition, but it’s important to note that no genetic test is 100% accurate every time. The accuracy and sensitivity of the carrier screening can vary according to what particular mutation is screened for and more research is needed to identify the accuracy of the screenings as a whole, but they are considered to be reliable in a vast majority of cases.

If you have any questions or concerns about the carrier screening results that you received, the best course of action is to speak with a genetic counselor. They will be able to better explain your results, describe the accuracy of your screening, and suggest any additional testing that may be necessary.