Thrombin time

Alphabetical Test listing

Thrombin time-510

Thrombin time
Sodium citrate (Na cit) plasma

Lt blue Sodium citrate (Na Cit) - 2.7mL 

If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube.

Hematocrit-Anticoagulant adjustments

1.5 mL
0.6 mL
  • Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical

Coag – tube fill guidelines

  • Immediately following collection, mix by inverting 8 - 10 times to prevent clotting
  • Process Platelet Poor Plasma (P.P.P)
  1. Coag – how to prepare a specimen for special coagulation testing



Microcentrifuge vial/tube in a Snap cap conical vial/tube and cap (Beaker sites)



Coagulation specimen transport vial/tube  (all other sites)





STAT requests only:

Send whole blood sample in original collection container with STAT courier.

Must be tested within 4 hours of collection.


Lt blue Sodium citrate (Na Cit) - 2.7mL 



Frozen (strict)

Refrigerated - NO

Ambient - NO


Ambient - 4 hours

  • Samples collected in Greiner tubes
  • Improper anticoagulant
  • Improperly (over or under) filled tube
  • Hemolysis
  • Patient on heparin > 1.0 IU/mL
  • Exceeds standard testing time
  • Incorrectly labeled or mislabeled
  • Clotted specimen
  • Plasma samples not completely frozen
AHL - Coagulation: W
1 day

Clot based assay


<16 sec


Prolongation of the thrombin time indicates:

  • An abnormality of fibrinogen
    • Qualitative; dysfibrinogenemia
    • Quantitative congenital: hypofibrinogenemia or afibrinogenemia
    • Quantitative acquired: DIC, fibrinolysis, liver disease
  • The presence of antithrombins
    • Therapeutic: heparin, hirudin, argatroban