I should be writing to the consultant to get more information, expressing my concerns, asking him what difference that type of testing (with the drug) makes to the diagnosis, ask him what amounts of what drugs are used and if it’s absolutely necessary. Also ask him how the body gets rid of the drug afterwards and what risks there are. At least, when he replies, you’ll be able to make a more informed decision and then have it in writing, so you’ll be able to investigate further, before you go.
Barbara
(UK)