A blood draw needle holder is modified on the outside surface of the closed end and the inside surface of the open end so that the closed end of one holder interlocks with the open end of another holder. As a result, one holder with no needle, but identical with another holder with a contaminated needle, may be locked in place over the contaminated needle. In addition, a stationery locking socket is provided for placement on a phlebotomist's tray or cart for locking a new unused holder in place, with the open end of the unused holder facing upright. Thereafter, the phlebotomist inserts the contaminated needle end with its used holder into the unused holder and locks the two together. With such an arrangement, no cumbersome telescoping shield is required on the holder being used for taking a blood sample. A conventional blood draw procedure takes place. The cost is reduced substantially since all holders, whether being used for blood draw or as a shield are identical and made from the same mold. Moreover, a plurality of identical holders may be placed in a single container on the phlebotomist's tray for quickly grabbing one for blood draw use or cover use.