Spot unrefined gold first in Yankee examination (7)
I believe the answer is:
autopsy
'examination' is the definition.
(autopsy is a kind of examination)
'spot unrefined gold first in yankee' is the wordplay.
I cannot really understand how this works, but
an anagram of 'spot' is 'tops' which is within the answer.
'gold' could be 'au' (Au is the chemical symbol for gold) and 'au' is found within the answer.
'yankee' could be 'y' (phonetic alphabet: alpha, bravo, charlie etc.) and 'y' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for autopsy that I've seen before include "Post-mortem inspection" , "A post-mortem examination of corpse" , "Far from quick examination" , "An official post-mortem examination" , "Examining body" .)