PLAYERS should not be considered to have passed a concussion test unless doctors have given them the all-clear to play, says Geelong coach Chris Scott. 

The issue became clouded last Saturday after St Kilda coach Alan Richardson gave the impression his skipper Nick Riewoldt was kept off the ground against Collingwood despite passing the concussion test.

Richardson later clarified that the club doctors correctly based their decision to remove Riewoldt from the game on vision that showed the 33-year-old displaying concussion symptoms when he received a knock.

Scott said people needed to be mindful there is no black and white concussion test that determined whether or not a player should be cleared to continue playing.    

"The ultimate test at the end of the day is the doctor's decision," Scott said.

"So if the doctor says 'no', you have failed the test. There is no set of cards that you need to select correctly to get back out on the field."

AFL.com.au understands the perception was raised at Monday night's concussion working group, with attendees keen to reinforce that a player had only passed a concussion test when the doctor gave him the OK.

Scott said Geelong trusted people in the club with the responsibility to assess their players when they received head knocks, and expressed frustration at the willingness of some commentators and external experts to comment on players' situations without knowing the full detail.  

"We trust our people internally and the consultants that we use and understand our players situations as individuals," Scott said.

"We don't take risks. We don't guess with our players. We're absolutely sure."