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THROMBIN TIME

Mnemonic

TT

Synonym

TT - Thrombin Clotting Time

Guidelines

Heparin, Direct Thrombin Inhibitors (Lepirudin, Argatroban, Dabigatran, etc.), Fibrin/fibrinogen degradation products may cause prolongation of the Thrombin Time. Other interferences include: Hemoglobin (>500 mg/dL), Triglycerides (1,000 mg/dL), Bilirubin (>24 mg/dL).

Specimen Collection Requirements

Collect

Whole Blood, light blue (3.2% Buffered Sodium Citrate) top tube

Handling

See Coagulation Specimen Collection Guidelines. Due to short stability, whole blood specimen tubes must reach the testing department within 4 hours, otherwise submit frozen plasma aliquots. NOTE: Frost-free refrigerator freezers are not acceptable for frozen sample storage. If proper storage is unavailable at the collection site, freeze/store aliquots on dry ice. Alternatively, send the patient to the nearest Legacy Hospital Outpatient Lab for sample collection/processing.

If submitting whole blood, transport at ambient temperature (15-25°C) in original unopened tube. If submitting frozen plasma aliquots, specimens must remain frozen (-20°C) during transport.

Preferred Volume

Two 2.7 mL whole blood or two 1.0 mL frozen plasma aliquots

Minimum Volume

One 2.7 mL whole blood or one 1.0 mL frozen plasma aliquot

Transport

Whole Blood: Ambient (15-25°C) 

Plasma: Frozen (-20°C), aliquots must remain frozen during storage and transport

Rejection Criteria

Whole Blood Refrigerated (2-8°C)

Clotted samples, samples collected in containers other than 3.2% Buffered Sodium Citrate, tubes filled less than 90%, samples from patients with a Hematocrit greater than 55%, hemolyzed samples, whole blood samples that were frozen before processing

Stability

WHOLE BLOOD: Ambient: 4 hours 

PLASMA: Ambient: 4 hours; Frozen (-20°C): 2 weeks, Frozen (-70°C): 6 months

Testing Information

Performed

Daily, Mon-Friday

Reported

48 hours

Method

Clotting

Reference Values

Reference Values

Varies, see report.

Critical Values

>100 seconds

CPT Codes

85670

Last Updated: Thursday, January 5, 2017 03:41:40 AM


Client Services: 503-413-1234