Referring to FIG. 1, a typical prior art phlebotomy system or blood sampler "bs" used for the withdraw of blood generally has a double ended hollow needle or needle cannula "n", a cylindrical barrel or holder for the needle "b", and a vacuum tube or evacuated receptacle "r". A first end "fe" of the double ended needle is inserted into a vein and the second end "se" is adapted to be inserted through a puncturable cover "c" of the evacuated receptacle. The second end of the needle has a rubber sleeve "s" thereover which operates as a valve and is pushed down over the second end of the needle as the puncturable cover of the evacuated container is pushed onto the needle. As soon as the second end of the needle emerges on the other side of the cover inside the receptacle, the vacuum therein instantly draws a sample of blood into the receptacle. An advantage of this arrangement is that with the first end of the needle still inserted into the vein, an operator, such as a nurse or lab technician, can collect a number of samples for different types of blood tests by merely inserting in succession a number of vacuum tubes over the second end of the needle. The described phlebotomy system is well-known in the art under the brand name Becton Dickinson VACUTAINER Systems, located in Rutherford, N.J.
A problem with the vacuum tube phlebotomy system as just described is that when the first end of the needle is withdrawn from the vein, it remains exposed and can be a source of great danger to the operator or to anyone who might be pricked or scratched by the exposed end of the needle. Needle injuries may result in the transmission of diseases such as hepatitis and HIV and may also lead to infection. One common solution available to the operator was to simply drop the needle and its holder into a trash receptacle. Another solution is to attempt to recap the needle with a safety cover immediately after use. This, however, may in itself cause injury if the operator should accidently stick themselves during the recapping process.