Routinely mail specimens the same day they are collected. If this is not possible, you may refrigerate specimens overnight, but do not freeze them. Butterfly' collection systems are not recommended, because the tubing is not anticoagulated. Clotting can begin in the tubing before blood comes in contact with EDTA in the collection tube. Avoid overfilling the collection tube.
Tubes contain only enough anticoagulant for the stated fill volume.
Remove the capillary tube and close the cap before mixing. Fill the capillary tube quickly to avoid clotting in the tube before it is mixed. To increase blood flow , ensure that the collection site is warm, obtain a good puncture, and position the collection site below patient's heart. Always wipe away the first drop of blood. This first drop contains tissue fluid and clotting factors that can cause a specimen to clot quickly.