the.com/clean bill of health

means An official declaration or assessment that someone or something is in good condition, with no problems found.

from This one's nautical. A 'bill of health' was a certificate given to a ship's master confirming no infectious disease aboard at the port of departure — vital in the age of plague and quarantine, since a 'foul bill' meant the ship had sailed from a port with an outbreak. A 'clean bill' let the ship dock and trade freely elsewhere. The phrase sailed ashore into general English, eventually coming to mean any all-clear, medical or otherwise.