Tana Umaga bemoaned the leniency of referee Jaco van Heerden and TMO Shaun Veldsman after Shaun Treeby escaped a yellow card for a tackle that knocked out Blues' fly-half Piers Francis.
Stormers centre Treeby caught Francis on the chin with a swinging arm in the second half of Friday's Super Rugby clash at Newlands, and the resulting concussion makes him a major doubt for next week's match against the Chiefs.
Van Heerden and Veldsman reviewed the incident and opted to only award a penalty, rather than sending the Treeby to the sin bin.
It was a decision that frustrated Blues coach Umaga and he will seek further clarification on why no further action was taken.
"From what's happened in previous games you probably could say [it deserved a yellow card]," Umaga said.
"We've just got to deal with decisions that are made on the field.
"We knew going into this game the South African referees had been giving away a lot of yellow cards, and cards in general, so we talked a lot about being disciplined and we would expect that consistency throughout the whole game.
"I've got to go through the right channels in terms of reporting back - that's what we'll do to make sure we get some answers to some of the questions we have.
"There were some tough calls that we felt went against us but that's the way it goes."
To add insult to injury the Blues finished the match with 14 men after Matt Duffie was shown two yellow cards as they were beaten 30-22 by the Stormers.