UPDATE: Blood tests for Ambrisentan, Bosentan and Macitentan Written by Mary Ferguson on Friday 3rd of July 2020. A message on behalf of the UK’s specialist centres PH patients have been shielded during the COVID19 pandemic. Consequently in March, the UK centres all agreed to suspend blood testing for everyone prescribed an Endothelin receptor antagonist (Ambrisentan, Bosentan or Macitentan) . The current government advice is for shielding to end on August 1st. On the assumption that this date does not change we would like to reinstate regular blood testing for everyone from this date. Some people have been having bloods taken for other reasons and managed to get their liver function and full blood counts done at the same time. However, for most people it will be some time since they had any blood tests done. The UK centres would be grateful if you can arrange a test for some time during August. Please note there is no immediate urgency, as we do not want the GPs, phlebotomy services, labs or the team at your centre to be overwhelmed in the very first week. Please also be aware that all centres have agreed to standardise the frequency of the blood tests for patients which will be a permanent change. The standard instructions (unless you are specifically told to do something different) will now be; Bosentan (Tracleer and generic brands) – Monthly liver function test and 3-monthly full blood count Ambrisentan (Volibris®) – 3-monthly liver function and full blood count Mactientan (Opsumit®) – 3-monthly liver function and full blood count These instructions will fit with the safety requirements that prescribers need to abide by, but there may be a medical reason why your tests need to be more frequent to this. If this is the case, please continue with the schedule your centre needs from you. Your centre will be in touch with this information in due course, but as so many people visit this website, they have asked that we give you some advance warning! If you would like any more information or have other concerns about blood tests, please do not hesitate to contact your PH specialist centre.