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Thrombin Time

Test Name:Thrombin Time
Epic Order Code:LAB324
CPT Code:85670  
Specimen(s) Type:Plasma; Full tube required.
Acceptable Container(s):Tube top is light blue.
Testing Schedule:24 hrs day, 7 days/week
Turn Around Time:STAT: NA  
 Routine: 2 hours
Collection Information:No special patient preparation is required. Obtain specimen by standard collection procedures. If only Thrombin Time is being collected, draw 5 mL into a red top tube, discard and then collect Thrombin Time tube. A full tube is required.
Transport Information:Deliver to lab immediately. All specimens must be signed into the laboratory.
Reference Clients:If unable to deliver to the lab within 1 hour, centrifuge the specimen for 10 minutes at 3500 RPM to ensure platelet poor plasma. Remove plasma from cells, taking care to avoid the WBC/platelet buffy layer and place into a transport tube. Store and transport at room temperature for up to 4 hours. If testing is delayed beyond this, the sample must be stored and transported frozen at -20° C and delivered to lab within 2 weeks.
Causes for Rejection:Improperly labeled, incorrect container, contaminated, insufficient quantity, incorrect/delay in transport, grossly hemolyzed, clotted, under or over-filled tube.
Reference Range:0.0 - 24.0 seconds
Additional Information:This test is extremely sensitive to heparin, and heparin contamination may give a falsely elevated result. Collection of blood for coagulation testing through intravenous lines that have been previously flushed with heparin should be avoided, if possible. If the blood must be drawn through an indwelling catheter, possible heparin contamination and specimen dilution should be considered. When obtaining specimens from indwelling lines that may contain heparin, the line should be flushed with 5 mL saline, and the first 5 mL of blood or 6 times the line volume (dead space volume of the catheter) be drawn off and discarded before the coagulation tube is filled. For those samples collected from a normal saline lock (capped off venous port) twice the dead space volume of the catheter and extension set should be discarded.