Anticoagulants Outside The Body
Laboratory instruments, blood transfusion bags, and medical and surgical equipment will get clogged up and become nonoperational if blood is allowed to clot. In addition, test tubes used for laboratory blood tests will have chemicals added to stop blood clotting. Apart from heparin, most of these chemicals work by binding calcium ions, preventing the coagulation proteins from using them.
- EDTA is denoted by mauve or purple caps on Vacutainer brand test tubes. This chemical strongly and irreversibly binds calcium. It is in a powdered form.
- Citrate is usually in blue Vacutainer tube. It is in liquid form in the tube and is used for coagulation tests, as well as in blood transfusion bags. It binds the calcium, but not as strongly as EDTA. Correct proportion of this anticoagulant to blood is crucial because of the dilution. It can be in the form of sodium citrate or ACD.
- Oxalate has a mechanism similar to that of citrate. It is the anticoagulant used in fluoride (grey top) tubes.
For the meaning of more test tube top colors, see Vacutainer#including coagulants.
Read more about this topic: Anticoagulant
Famous quotes containing the word body:
“We are such docile creatures, normally, that it takes a virus to jolt us out of life’s routine. A couple of days in a fever bed are, in a sense, health-giving; the change in body temperature, the change in pulse rate, and the change of scene have a restorative effect on the system equal to the hell they raise.”
—E.B. (Elwyn Brooks)