What is the test for amendmentary costs in a personal injury action?

The general rule is that an amendment should be allowed at any stage of an action for the purpose of determining the real questions in a controversy between the parties, provided that it will not result in an injustice to the other party not capable of being compensated through costs, and provided that it would serve the interests of justice (Canderel v. R., 1993 CanLII 2990 (FCA), [1994] 1 F.C. 3 (F.C.A.)).