i have a GP that had to monitor my iron status and b12 levels throughout the the latter years of my 'vegan era'. i was a complete idiot back then, did everything wrong.
after my msdx, the doc was receptive to the stack of literature i brought in to support my early request for nutrition testing beyond my usual stuff (vitamin D3 was my first step towards MS-related testing).
OHIP pays for a bunch of stuff, but not everything. the govt just took vit D3 off the list of things they cover, with certain exemptions of which ms patients are not one. any time i've paid for a test it's been around 30 to 35 dollars, but i hear d3 can go as high as 200, so shop around (unless you qualify for an exemption under the new rules - if you do you might still get free d3 testing)
i have never ever asked for an ET-1 test but there is a schedule of tests covered by OHIP and if i found it was covered, then took in the relevant abstracts to my doc, i imagine i could ask for a requisition. however, it's more for academic interest not need per se so i may not follow through on the ET-1 idea.
i'm the one to blame for curiosity and i have NO medical qualifications, and i don't work in the field either. i have background in environmental studies with a specialization in ecosystem restoration.
my approach is very much viewing self as ecosystem and restoring it using nutritional status as an array of 'indicators', and using healthy controls as 'reference sites' to compare and assess and monitor over time.
so anyway, i depend on my doc for everything except research and assessment of results. all i have is a good background in assessing scientific research and a pretty vested interest in keeping the ecosystem that is me, in tip top condition.
at this stage of the game when i walk in my doc's office for any appointment i might have a post-it with a list of tests written on it and without my specifically asking for a requisition, when the doc spots it the requisition pad comes out, and i say thanks and head to the lab.
later i get the results (which are almost always 'normal') and assess whether they are 'healthy normal' or 'ms normal'
and then i come and post the results here