hi
the consulate in uk advised me not to get the medical cert before coming to paraguay. this was because it would have to be translated adding extra expense. i am not sure whether it would need to be legalised.
obtaining the medical certificate is available in asuncion. i took the public health cert route, which was interesting as i was a nurse and saw how hospitals work here. it took a long time.
i needed blood tests, dermatology, ecg, medical and psychological tests.
i would for speed recommend that you go the private route here. i private doctor will do all of these tests. i was kindly sent a couple addresses by other members, but didn't use them as i had already begun the public route.