Sodium Citrate either 3.2% or 3.8%
Citrate, theophylline, adenosine, dipyridamole (CTAD)
Citrate is an anticoagulant which binds calcium in the blood. Calcium is required for blood clotting. Since it is bound up the blood cannot clot resulting in a whole blood sample, red blood cells and PLASMA. Coagulation tubes are filled with buffered tri-sodium citrate solution. Citrate concentrations of either 0.109 mol/l (3.2 %) or 0.129 mol/l (3.8 %) are available. The choice of the concentration depends upon the policies of the laboratories. The mixing ratio is 1 part citrate to 9 parts blood. CTAD tubes contain besides the buffered citrate solution, theophylline, adenosine and dipyridamole.
These tubes MUST BE COMPLETELY FILLED due to the amount of additive in the tube. Short draw tubes will be rejected.
The Coagulation department in the clinical laboratory performs various tests on citrate-anticoagulated blood specimens to determine coagulation disorders and to monitor patients receiving anticoagulation therapy such as heparin, coumadin or warfarin. A clotting profile is performed on specimens, as a screening test. According to the results of the profile, further specialized tests may be performed to determine coagulation factor deficiencies, platelet abnormalities, hypercoagulability, etc.
Site with list of some very special coagulation tests: Duke University Regional Referral Laboratory Services
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