Quality of blood tests and vitamin supplements in Thailand

Hi all

I need to take vitamin B12 supplements to combat a severe deficiency. As a follow-up, my doctor asked me to have blood sampled every 3 months to see how the B12 level evolves. My next blood sample should be taken around mid-October, at which time I’ll normally be in Thailand as part of a world trip . Does anyone have experience with getting blood tests done in Thailand? I’m curious to availability, how to arrange, cost price, and if they’ll give me a printed blood report that I can send to my doctor.

I’m packing plenty of B12 pills, but in case something happens to it:

* Can vitamin pills be bought at any pharmacy OTC, and how much would they cost?
* Should I look out for quality issues/specific brands to avoid?

Sorry if this post fits better in r/thailand, I was thinking other travellers may have been in this exact situation and could share their experience.

Many thanks!

Quality of blood tests and vitamin supplements in Thailand