What is a genetic test?

How is a genetic test carried out?

A genetic test takes the form of a blood or tissue sample (mouth swab) from a patient that is analysed in a laboratory. The DNA in the cells is chopped up into tiny pieces and sorted, so that that person’s unique genetic sequence can be deciphered by a computer. The DNA sequence is then screened for known IRD-causing mutations.

If you would like to learn more about genome sequencing, watch the following video: How to sequence the human genome by Mark J. Kiel (TED-Ed)

Please be aware, that unless patients request that their sample be discarded after testing, a laboratory will usually store the DNA for research use. Laboratories will be happy to let you know about your sample, and individuals can request at any time that their DNA be destroyed or returned to them.

Can results be wrong?

Because a genetic test has very important implications for the individual and their family, they are treated very carefully. Numerous steps are taken to ensure that the correct result is given:

1. If a mutation is found it is always double checked to ensure that the result is correct.
2. Often, scientists will perform another test to ‘cross check’ the first result.
3. Procedures are also in place to make sure that samples do not get mixed up.
4. Additionally, many laboratories take part in Quality Assurance (QA) schemes which help ensure that they perform good quality and reliable genetic tests.