Ultimate sign of diabetes: urine sample containing most sugar (8)
I believe the answer is:
sweetest
'ultimate sign of diabetes urine' is the definition.
I can't tell whether this definition defines the answer.
'sample containing most sugar' is the wordplay.
I cannot really understand how this works, but
'sample' could be 'test' (I've seen this in another clue) and 'test' is found in the answer.
The remaining letters 'swee' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sweetest that I've seen before include "Most tender" , "Most appealing" , "most attractive" , "Most Melliflous" , "dearest" .)