Is it ever wrong about blood group types? (9)
I believe the answer is:
varieties
'types?' is the definition.
(type is a kind of variety)
'is it ever wrong about blood group' is the wordplay.
'wrong' is an anagram indicator.
'about' means one lot of letters goes inside another.
'blood group' becomes 'a' (A is an example).
'is'+'it'+'ever'='isitever'
'isitever' is an anagram of 'vrieties'.
'vrieties' enclosing 'a' is 'VARIETIES'.
(Other definitions for varieties that I've seen before include "one used to find in a palace?" , "Assortments,diversities" , "All sorts" , "Assortments, mixtures" , "Types" .)