A plunger locking assembly is provided for a syringe which has a barrel and a plunger. The barrel has a closed end with a cannula connector, an open end bounded by a peripheral lip and a barrel longitudinal axis extending between the closed end and the open end. The plunger has a plunger inner end, a plunger outer end and a plunger longitudinal axis extending between the plunger inner end and the plunger outer end. The plunger is slidably displacable within the barrel to different longitudinal lock positions and the barrel and plunger longitudinal axes are coextensive with one another. The plunger locking assembly includes a main body and a plunger locking mechanism. The main body has an inner end, an outer end and a main body longitudinal axis and is adapted to engage the plunger. The plunger locking mechanism is positioned on the main body and is adapted to lock the plunger at a fixed longitudinal lock position within the barrel to prevent further slidable displacement of the plunger into the barrel.