Safety syringe for fluid collection

A safety syringe comprising:

• a substantially hollow barrel having a needle end, a plunger end, and an interior wall extending between said plunger end and said needle end, wherein said needle end, said plunger end and said interior wall define a fluid receiving cavity within said barrel;
• a plunger extending from said fluid receiving cavity of said barrel, said plunger having a thumb end and a washer end, said washer end configured to create a substantially fluid tight seal between said washer end and said interior wall of said barrel, whereby operation of said plunger will vary the volume of said fluid receiving cavity;
• a retractable needle extending from said barrel, said needle having a sharp end, said needle providing fluid passage into said fluid receiving cavity, said needle having an extended position and a retracted position, said needle functionally connected to said plunger to allow said needle to be retracted upon operation of said plunger;
• and
• a hollow sheath circumferentially positioned over said needle, said sheath extending from said needle end of said barrel, said sheath having a tip end, said tip end having an external diameter, said tip end sized to be hypodermically insertable with said needle, said sheath sized so that said sharp end of said needle is exposed when said needle is in said extended position, said sheath further sized so that said sharp end of said needle is contained within said sheath when said needle is in said retracted position, said sheath configured to provide fluid passage to said needle when said needle is in said retracted position.