A wound closure system and methods utilizes a patient's own blood. The system preferably includes a chamber with a needle and a plunger for transferring and storing blood prior to surgery and the use of reversible anticoagulants. The chamber is pre-loaded with a reversible anticoagulant to prevent the blood from clotting during storage. When the surgery is complete, a counteracting agent is mixed with the withdrawn blood to counteract the reversible anticoagulant and allow the blood to clot. The clottable blood is then reintroduced into the patient to close a wound.