short answer, no the tests are not all routine in relation to MS, except b12. they do a lot of bloodwork when they dx, but mostly it's for functionality of body processes. they don't tend to look too closely at the components that facilitate those body processes.
for d3 to make a difference, i'd say go for a serum value at least 100nmol/L 25-hydroxycholecalciferol. i aim for 150. there's only 30-odd years of research on the subject so far so it's still pretty arbitary.
long answer, if you're going to work with supplements, get tested don't do it blind. be as systematic as you can. don't trust normal lab results - find out from the literature what you want your values to be, and work towards them.
don't let any old symptom get lumped into your msdx. for me, a strange nerve problem with itching turned out to be folic acid toxicity because i had started a new bottle of b-complex that was out of balance.
i know my "normal" uric acid result is actually right on the ms average and should be 290 to be optimal, so i'm going to have to work on that.
i know i'm zinc deficient from bloodwork i requested, and whatever was going wrong due to that would have gotten lumped into the MS round file too, if i had not asked for the test.
finally, the numbness in my hands is now actually carpal tunnel syndrome, due to recent testing (not bloodwork that time) but for 2 years it was part of my MS.
so when you supplement and feel an effect, be very cautious about labelling the results "MS symptoms".
for d3, the daily amount really depends. Just talking about targets to aim for, for serum 25-hydroxycholecalciferol levels you want to be above 50nmol/L to keep rickets away, above 80nmol/L to keep osteoporosis away, and above 100nmol/L to keep the immune system in shape. (note that in sunny half-naked environments, unsupplemented serum levels can be much much higher than that with no adverse effects, such as hypercalcaemia).
The literature out there asserts that human skin with arms legs and torso exposed (without having read all the details lately, i’m assuming the pale youthful variety of skin) can make 10,000IU of D3 in 30 minutes. (that’s also assuming a clear day, with at least 18 (i forget the units) of solar energy hitting the skin, so that the d3 manufacture will start up - where i live the sun is only strong enough for that between may and October-ish). It has also been asserted that humans generally utilize 4000IU of d3 per day, so that is posited as a 'maintenance' dosage.
there’s also research out there that lets you calculate how long you will need to supplement at a given daily rate to achieve a certain serum level. i’m pretty sure it’s all posted on the site here somewhere but let me know if you want me to dig for it, i compiled some of this stuff off the site not too long ago so if you want it, just say.
overall let's just say, you want to get your serum levels up to 150 nmol/L for part of the year, and no lower than say, 80nmol/L for the rest of the year. Without doing any calculations at all, you can schedule two d3 tests per year, one in the early fall and one in late spring say, and you’ll know from that if you’re taking enough. Always take magnesium and calcium and zinc with d3. You need 1000-1200mg of calcium daily when you’re supplementing higher levels of D (the exact daily amount is posted on another study here somewhere, which we can track down if you want). I’m still working on the magnesium and calcium ratio because when i just ramped all the minerals up, my kidneys ached. When i just took one cal-mg-zn-d3 pill with my 4000IU d, it may not be directly linked, but i ended up zinc deficient according to the lab, and i think i caught and corrected the mg deficiency before it had a chance to show up on paper.
and of course that won't be more than the tip of the iceberg for the complexity of d3 interactions, but those are the big ones that i know about right at the moment.
Anyway, on to my other tasks for the day!