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Test Code 4384 Thrombin Time, Plasma

Performing Laboratory

Barnes-Jewish Hospital Laboratory

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

Specimen Requirements

Specimen Type: Plasma

Container/Tube: Light-blue top (citrate)
Specimen Volume: 1  Full tube
Specimen Minimum Volume: Full tube
Collection Instructions:

1. Draw a discard tube prior to light-blue top (citrate) tube.

2. Tube should remain stoppered.

3. Do not centrifuge.

4. Clotted blood or an insufficient specimen is not acceptable.

5. Avoid hemolysis and heparin contamination of specimen.

Analyte Stability:

Nonheparinized:
24 hours at 2° C to 24° C.
Platelet free plasma can be stored 6 months at -70° C

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

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

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

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.
Platelet free plasma can be stored 6 months at -70° C

Heparin therapy:

2 hours at 18° C to 24° C.

Laboratory Processing Instructions:

Test performed in BJH Hematology.

Specimen Transport Temperature

Ambient/Refrigerate NO/Frozen Yes

LOINC Code Information

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