Thai Red Cross is the best, works out about 400 baht a month, they have Thai or Indian generic. They do the HIV and Creatinine tests also. Quite a slick process which takes 1-2 hours. Initially will give you 1 month only, on subsequent visits will give you 4 months worth.
The Thai Red Cross AIDS Research Centre
02 251 6711
https://maps.app.goo.gl/bjBy4nS8h8ke3vHa7