Sign in →

Test Code LAB324 Thrombin Time, Plasma

Methodology

Absorbance measurement, Clot signature formation
Testing Algorithm:
If thrombin time is >25 seconds, the test is repeated with protamine sulfate added to confirm or rule out the presence of heparin, at an additional charge.
Literature References:
Package insert:  HemosIL Thrombin Time (pn9758515) determination by the ACL TOP, Instrumentation Laboratory, 12/2016

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Specimen Requirements

Specimen Type: Plasma

Container/Tube: Light-blue top (citrate)
Specimen Volume: Full tube
Specimen Minimum Volume: Full tube
Collection Instructions:

  1. Draw a discard blue top tube prior to drawing a light-blue top (citrated) tube if using a Winged Infusion Set.  Discard tube should be under filled and discarded.
  2. Clotted blood or an insufficient specimen is not acceptable.
  3. Avoid phlebotomy techniques which cause hemolysis and heparin contamination.
  4. Follow nursing policy on volume of blood to discard prior to collecting blood from indwelling heparinized catheters.

Analyte Stability:

Nonheparinized:
24 hours at 2° C to 24° C.

Platelet-free plasma can be frozen at -20 for transport on dry ice up to 72 hours
or stored 6 months at -70° C.

Heparin therapy:
2 hours at 18° C to 24° C.

Platelet-free plasma can be frozen at -20 for transport on dry ice up to 72 hours
or stored 6 months at -70° C.

Additional Information: If the patient is a hospital patient and the hematocrit is >55%, call Barnes-Jewish Hematology Laboratory at 314-362-5203 for instructions.

Specimen Transport Temperature

Ambient Yes/Refrigerate NO/Frozen Yes

Reference Values

10-15 seconds

Confirmation results appear in the report as thrombin time-protamine corrected.
Physician alert value (automatic call-back): >30 seconds on correction

Day(s) Test Set Up

Monday through Sunday

Turnaround Time:

STAT: 1 hour after receipt in laboratory

Routine: 2-4 hours after receipt in laboratory

Test Classification and CPT Coding

85670-Thrombin time, plasma

85670-Confirmation (if appropriate)

Additional Information

For BJH Laboratory Use Only

Analyte Stability:

Nonheparinized:

24 hours at 2° C to 24° C.

Heparin therapy:

2 hours at 18° C to 24° C.

Heparin and Non-heparinized:

Platelet-free plasma can be frozen at -20 for transport on dry ice up to 72 hours
or stored 6 months at -70° C.

Laboratory Processing Instructions:

Test performed in BJH Hematology.

LOINC Code Information

Name LOINC Code
Thrombin Time, Plasma 3243-3
Thrombin Time, Protamine Corrected 33673-5