SharpShield allows single-hand injection requiring virtually no change in standard techniques. The safety device passively activates subepidermally when a form-fitted sheath slides over the needlepoint after the medicine is administered. This occurs before the needle is removed from the patient preventing exposure to the contaminated needle. The plunger locks to ensure one-time use and low dead space. Unlike auto-retractable syringes, SharpShield does not cause blood splatter upon activation or removal.