Poorest procedure to determine allergy (4,4)
I believe the answer is:
'allergy' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for skin test that I've seen before include "medical procedure?" , "Medical check" , "Check for allergy" , "Trial to determine immune reaction" .)