Good and informative post.
I'd just like to sing the praises of The Red Cross Anonymous Clinic..
I went there for an H.I.V. test on the advice from a doctor at Chulaloncorn Hospital ("It's cheaper there than here and we are the same organisation"). (actually 210 Baht and the results either personally or by email one hour later)
To find the clinic, (walking) follow the skytrain above you to half way between Sala Daeng and Ratchadamri stations. It is under the water towers on your left. Cannot miss it. Everyone there, from doorman to nurse are so nice and helpful.
Being a crusty old fart, I had trouble filling the registration form but a lady went out of her way to help me, so it might be an idea to register earlier online.
The clinic(Red Cross) and Chula hospital (Chula university) seem to be the same organisation BUT who owns whom?
Sorry to go off piste a little but does anyone know if they also do non sexual blood tests like cholesterol, blood glucose etc.?