Test Code LAB324 Thrombin Time
Useful For
- Assessing fibrin formation
- Increased thrombin time may indicate an abnormality of fibrinogen such as:
- dysfibrinogenaemia
- severe hypofibrinogenemia
- congenital afibrinogenemia
- acquired hypofibrinogenemia (DIC, fibrinolysis, liver diseases)
- Increased thrombin time can also be seen in the presence of antithrombins:
- Therapeutic: heparin, hirudin, argatroban, etc.
- Abnormal: FDP, appearing during myelomas, etc.
Methodology
Clot Detection
Performing Laboratory
Bozeman Health Laboratory Services
Specimen Requirements
Specimen Type: Whole blood
Container/Tube: Blue top (3.2% sodium citrate)
Specimen Volume: Full tube
Collection Instructions: Click here to link to a You Tube video tutorial
1. Immediately after draw, invert tubes several times to mix blood with additive.
2. Send specimen in original tube.
3. If there is a delay in transport of >4 hours, specimen must be double-centrifuged to prepare a platelet-free plasma specimen as follows:
a. Immediately centrifuge at 3,200 rpm for 15 minutes.
b. Carefully remove plasma from cells avoiding platelet/buffy coat, and transfer plasma into a plastic tube.
c. Centrifuge plastic tube at 3,200 rpm for 15 minutes.
d. Carefully remove top portion of plasma and transfer plasma into a plastic tube leaving approximately 250 mcL in bottom to discard.
e. Double-centrifuged plasma should be aliquoted (0.5 mL-1 mL each) into clearly labeled plastic tubes. (Glass vial is not acceptable.)
Note: Number of tests ordered will determine number of aliquots needed, generally 1 aliquot per test.
f. Specimens should be frozen at <-40° C, if possible, and sent together in same container with at least 5 lbs of dry ice. Specimens must arrive in a frozen state.
Additional Information: Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
Specimen Transport Temperature
Ambient (whole blood) <4 hours/Frozen (plasma) >4 hours
Specimen Stability
Specmen Type | Temperature | Time |
---|---|---|
Whole Blood (unspun) | Ambient | 4 hours |
Plasma Na Citrate | Ambient | 8 hours |
Frozen | 14 days | |
Plasma Na Citrate (on Heparin Therapy) | Ambient | 2 hours |
Reference Values
15.0-18.0 seconds
Day(s) Test Set Up
Monday through Sunday
Test Classification and CPT Coding
85670