How to Read a Genetic Test Result (Positive / Negative / VUS)
Definition
A genetic test result falls into three main categories:
| Result | What it means | What it does not mean |
|---|---|---|
| Positive | The laboratory found a change in the gene, chromosome or protein of interest. It may confirm a diagnosis, indicate carrier status, or point to an increased risk | Not every positive means "you are ill"; carrier status is also a positive result |
| Negative | The laboratory did not find a change known to affect health or development. | It does not mean "you are healthy", see below |
| Uncertain (VUS) | A result that provides no useful information, covered below as a separate entry | , |
The limit of a negative result, the most commonly misunderstood point:
A negative result cannot prove that the person is definitely unaffected; the test may have missed the genetic change causing the disease, because many tests cannot detect all the genetic changes that can cause a particular disorder.
"Uninformative" result: This arises because of common DNA polymorphisms that are unrelated to health. Such a result cannot confirm or rule out a specific diagnosis and cannot show whether the person has an increased risk.