Antidote ready? Blood group must be changed for me (6)
I believe the answer is:
remedy
'antidote' is the definition.
(I've seen this before)
'ready? blood group must be changed for me' is the wordplay.
I cannot quite understand how this works, but
'me' is within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for remedy that I've seen before include "solution" , "answer" , "Curative medicine" , "Medication" , "A cure, for disease or other ill" .)