The anticoagulant of choice for performing coagulation studies is -
The most commonly use anticoagulant for in vitro Coagulation Studies is Citric Acid.It is generally employed in the form of Sodium Citrate.
In Vitro use of anticoagulants

For coagulation studies-Sodium Citrate
For Hematological studies-EDTA
For estimation of ESR


Wintrobes method-Double oxalate.
Westergren method-Sodium Citrate.
EDTA
Heparin
Tri sodium citrate
Double oxalate