Whattesting involves

There are usually two steps to genetic testing:

  1. Arelative with cancer has a diagnostic blood test to see if they have a cancer risk gene (this normally must happen before any healthy relatives are tested). Their result will be readyfour to eightweeks later.
  2. If your relative's test is positive, you can have the predictive genetic test to see if you have the same faulty gene. Your GP willrefer you to your local genetics service for the blood test (you'll need a copy of your relative's test results). The result will takeup totwo weeks to come through after a blood sample is taken, butthis may not happen atyour first appointment.This test is fully predictive as a "clear" negative test, which will mean you have not inherited the family high risk of cancer.

The charity Breakthrough Breast Cancer explains the importance of these two steps:

"Without looking at the genes of an affected relative first, testing a healthy individual would be like reading through an entire book looking for a spelling mistake without knowing where the mistake is, or if there is a mistake at all."

When there are no affected relatives available, full testing of BRCA1 and BRCA2 may be possible for those with at least a 10% chance of having a genetic fault. This usually means having a very strong family history of early onset breast and particularly ovarian cancer. It takes four to eight weeks to get the result, but this is not fully predictive as a negative test, so cannot rule out that the problem in relatives is due to a different gene.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 21 Dec 2018