This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
The anticoagulant of choice for performing coagulation studies is - 
Select and explain. 
A. EDTA, B. Heparin, C. Tri sodium citrate, D. Double oxalate
C: Tri sodium citrate
Answer: C: Tri sodium citrate 
Explanation: 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.