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Test Code HTT Thrombin Time, Heparin removed

Specimen Type



Light blue top tube, 3.2% sodium citrate

Preferred Volume

2.7 mL

Offsite Collection Instructions

  • Samples must be centrifuged at >1500 x g for 10 minutes at room temperature.
  • Carefully remove the plasma from the cells using a plastic transfer pipette avoiding the buffy coat.
  • Aliquot removed plasma into 2 plastic tubes containing minimum of 500 uL of specimen each.
  • The plasma samples must then be frozen at -20ºC.
  • Once solidly frozen they must be shipped on dry ice. Samples that have thawed in transit will be rejected.


Note: For clients who do not have access to dry ice do not freeze the specimen. Follow the centrifugation instructions or send whole blood sample. It now becomes vital that the specimen arrives in the lab within three hours of collection.

UCMC Collection Instructions

Specimens may be collected and sent to the laboratory at any time.

Test can be added on to an existing order up to 4 hours following the time of blood draw.



Turnaround Time

4 hours

STAT Availability

Not Available

Test Methodology


Additional Information

All 3.2% sodium citrate light blue top tubes require a ratio of 9 parts blood to 1 part anticoagulant (example: a 3.0 mL tube requires 2.7 mL blood added to 0.3 mL of anticoagulant).

CPT Code

85670 and 85525

Minimum Volume

2.7 mL

Reference Range

16-22 seconds

Fee Code

44236 and 44237

Test Includes

Thrombin Time Result after removal of hepain from the sample.