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Test Code 4379 Partial Thromboplastin Time (PTT), 50:50 Mix, Plasma

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Methodology

Absorbance measurement, Clot signature formation
Literature References:
HemosIL SynthASil (pn 20006800) package insert issued 02/2016, Instrumentation Laboratory.

Specimen Requirements

Specimen Type: Plasma

Container/Tube: Light-blue top (citrate)

Specimen Volume: 2 Full tubes

Specimen Minimum Volume: 2 full tubes

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 the specimen.

Analyte Stability:

4 hours at 18° C to 24° C if the top has not been removed.
2 hours at 18° C to 24° C after the top has been removed.
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: 2 hour after receipt in laboratory

Routine: 2-4 hours after receipt in laboratory

Reference Values

25.0-37.0 seconds (50:50 mix of patient and normal plasma will not correct a prolonged PTT if an inhibitor is present)
Physician alert value (automatic call-back): >150 seconds

Test Classification and CPT Coding

85730 x 2-PTT activated straight

85732 x 2-PTT activated 50:50

Additional Information

For BJH Laboratory Use Only

Analyte Stability:

4 hours at 18o C to 24° C if the top has not been removed.
2 hours at 18o C to 24° C after the top has been removed.
Laboratory Processing Instructions:

Test performed in BJH Hematology.

Specimen Transport Temperature

Ambient/Refrigerate NO/Frozen NO