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Hemostasis - Thrombin Time Mixing Study
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Test Description
Test Name
Thrombin Time Mixing Study
Synonym(s)
 
Description
The determination of the thrombin time is suitable for monitoring heparin therapy using high-molecular- weight heparins, for monitoring fibrinolysis therapy, for screening for disorders of fibrin formation and in cases of suspected severe fibrinogen deficiency states and for differentiating between heparin-induced prolongation of the thrombin time and fibrin formation disorders.
Methodology
Clotting
Performed
Monday – Friday
Turnaround Time
1-3 days
Specimen Requirements

3 mL platelet-poor citrated plasma (light blue 3.2% sodium citrate tube). Freeze plasma within 4 hours of collection in 1 mL aliquots.

Transport frozen.

Minimum volume 2 mL.

Coagulation Drawing Instructions:

  1. When drawing coagulation tests, always draw a "pilot" tube (7-10 mL plain red top tube, completely filled). This removes tissue fluid contamination, discard pilot tube.
  2. Draw blood in a light blue (3.2% sodium citrate) top tube. Fill tubes as far as vacuum will fill and mix gently. Ratio of anticoagulant and blood must be maintained. Avoid slow flowing draws and traumatic venipunctures.
  3. Spin vacutainer – remove plasma avoiding platelet/buffy layer – spin plasma again – remove top portion of plasma and place 1 mL of PLATELET-POOR PLASMA in plastic tube. (Glass tube unacceptable)
  4. Double-centrifugation is critical for accurate results as platelet contamination may cause erroneous results.
  5. Plasma must be frozen within 4 hours of collection.
  6. CRITICAL WARNING: Specimen must remain frozen until testing. Submit separate aliquots when multiple tests are ordered on same patient specimen.
Rejection Criteria
Plasma hemolyzed, thawed or contaminated with heparin.
CPT Code(s)
85670 x 3, 85390
Reference Range
See interpretive report.
Contact Information
Hemostasis Lab: 214-645-5067
Customer Service: 214-645-7057, Toll Free 877-887-8136
Last Modified: 01/05/2011