The lawyers for Sabastian Prosa, who was 19 at the time of the 2012 collision, had asked for 12 charges he faces to be dropped because a sample of his blood leaked during the investigation and couldn't be properly tested.
Justice Glenn Hainey said the loss of the blood sample did violate Prosa's charger rights, but said he wouldn't stay the proceedings. The judge is expected to make a ruling in the case at an upcoming court date.
Prosa was behind the wheel of a GMC Envoy that struck a van carrying Jayanatha Wijeratne, along with his wife, Antonette, and their 16-year-old daughter, Eleesha, in August 2012. Jayantha Wijeratne, 49, and his daughter died in the crash, while Antonette Wijeratne suffered severe injuries.
Prosa has pleaded not guilty to all charges against him.
At trial, he has admitted to driving the vehicle that night, as well as to having almost double the legal limit of alcohol in his system at the time. But Prosa says he believes his drink was spiked on the night of the crash, and his lawyer, Alan Gold, argues the loss of the blood sample affects Prosa's ability to mount a full defence.