The present invention ofthe round-bottom tube with a triple-lock stopper is a round-bottom test tube with an open end at the top and a closed end at the bottom, containing a removable stopper. The top ofthe tube has outer ridges for a screw cap and inner ridges for a removable tripleJock 5 stopper. The cylinder-shaped stopper features outer threads that mesh with the inner ridges ofthe round-bottom tube for a secure seal. Moreover, the triple-lock stopper contains an axial hole at its top end. The axial hole on the tripleJock stopper fits a hollow plastic rod with two open ends. The top end ofthe plastic rod has a rectangle shape with no inner ridges that fits a luer-lok tip syringe whereas the bottom end of the plastic rod has a trapezoid shape with inner ridges that fit a slip tip syringe.