medical devices for interfacing with an intravenous catheter to collect blood; vascular access medical devices for interfacing with an intravenous catheter to collect blood; intravenous medical devices for interfacing with an intravenous catheter to collect blood; medical devices for collecting blood through an intravenous catheter; vascular access medical devices for collecting blood through an intravenous catheter; intravenous medical devices for collecting blood through an intravenous catheter; medical devices for accessing vasculature through an intravenous catheter; vascular access medical devices for accessing vasculature through an intravenous catheter; intravenous medical devices for accessing vasculature through an intravenous catheter; blood collection medical devices for connecting a blood collection tube or syringe to an intravenous catheter; vascular access medical devices for connecting a blood collection tube or syringe to an intravenous catheter; intravenous medical devices for connecting a blood collection tube or syringe to an intravenous catheter; blood collection medical devices comprising a connector and a cannula extendable relative thereto; vascular access medical devices, namely, aspiration devices for drawing blood, comprising a connector and a cannula extendable relative thereto; intravenous medical devices, namely, aspiration devices for drawing blood, comprising a connector and a cannula extendable relative thereto