I just had mine done as was taking 2,500 iu for years and decided to have a new Vit D3 test. If you ask for printout from your GP if they did it it will say in my case result 35 g/l and normal guidelines of 35-50 g/l
My neuro bod said I should be taking a min of 5,000 iu but due to me just hitting min guidlines I have uppped that to 7,500 iu.
You level of 47.3 is not low but due to what I was told from my neuro bod vit d3 not only reduces relapses but could slow MS progression I would put it to your neuro bod what level should your blood show, MS nurses don’t know much or read latest studies.
This whole vit d3 thing is a bit annoying as Neurologists if they all agree what VitD3 can do should pick a number like 50 or 60 and say everyone should aim for that.
Neuro bods being vague with their advice is not helping anyone and I suggest everyone here to get a Vit d3 blood test before swallowing loads of pills.