Nicola Black is a 45 year old female who is 15+2/40 and this is her first pregnancy. Nicola has come to discuss the results of her combined test that she had yesterday. She informs you that she was explained that her tests have shown she was ‘high risk’ for Down’s syndrome. Nicola was devastated and caught off guard and did not ask any questions about what it meant. Nicola is keen to proceed with invasive tests if necessary, despite the risk of miscarriage as she would opt for a termination if Down’s syndrome was confirmed. You explain that she will be seen by a member of the obstetric team and offered a test which would give her a definite answer.
Which one of the following tests will she likely be offered?