Dynarex Blood Collection Tube HoldersDynarex Blood Collection Tube Holders The Dynarex Blood Collection Tube Holders have a slim, easy to handle design, enhancing the users control and flexibility. These tube holders are made of a translucent plastic for easy viewing of blood collection while providing a secure connection to blood collection tubes, needles and sets when performing a direct draw into a blood collection tube. The tube holders are available with a luer lock or luer slip