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Test Code TTSC Thrombin Time (Bovine), Plasma

Reporting Name

Thrombin Time (Bovine), P

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Detecting or excluding the presence of heparin or heparin-like anticoagulants (which act by enhancing antithrombin's inhibition of thrombin and other procoagulant enzymes) when used in conjunction with the reptilase time (RT) in evaluating unexplained prolonged clotting times

 

Identifying the cause of a prolonged prothrombin time, activated partial thromboplastin time, or dilute Russell viper venom time when used in conjunction with the RT and fibrinogen assay

Method Name

Optical Clot-Based


Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: Fasting preferred

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into a separate plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally,  -40° C or below.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.


Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

15.8-24.9 seconds

Interpretation

Prolongation of the thrombin time (TT) is consistent with the presence of heparin-like anticoagulants, hypofibrinogenemia, dysfibrinogenemia, fibrin degradation products, and antibody inhibitors of thrombin. An immeasurably prolonged TT is usually the result of heparin in the specimen or, rarely, the presence of thrombin antibodies or afibrinogenemia.

 

When the TT test is performed with diluted bovine thrombin to achieve a normal plasma clotting time of about 20 seconds, the TT is capable of detecting unfractionated heparin at a concentration of 0.05 units/mL of heparin.

 

Other tests useful in interpreting the significance of prolongation of the TT include: reptilase time (RT), human thrombin time, clottable fibrinogen assay, and the fibrin D-dimer assay. These tests are available as components of coagulation profile test panels. As seen in the following table, RT can help distinguish among the various causes of a prolonged TT.

 

Thrombin time

Reptilase time

Causes

Remarks

Prolonged

Prolonged

Hypo- or afibrinogenemia

Ascertain by determination of fibrinogen

Prolonged

Prolonged

Dysfibrinogenemia

Ascertain by specific assay

Prolonged

Normal

Heparin or inhibitor of thrombin

Differentiate by human TT and/or heparin assays

Prolonged

Prolonged

Fibrin(ogen) split products (FSP)

Ascertain by FSP or D-dimer assay

 

Note: Rare congenital dysfibrinogenemias associated with venous thromboembolism (eg, fibrinogen Bordeaux) may demonstrate normal thrombin and reptilase times and normal Clauss fibrinogen levels.

Day(s) Performed

Monday through Saturday

Report Available

1 to 4 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

85670

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TTSC Thrombin Time (Bovine), P 46717-5

 

Result ID Test Result Name Result LOINC Value
TTSC Thrombin Time (Bovine), P 46717-5

Forms

If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.