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Test Code LAB2311 Prothrombin Time (PT), 50:50 Mix, Plasma

Methodology

Absorbance measurement, Clot signature formation
Includes international normalized ratio (INR).
Literature References:
Package insert: RecombiPlasTin 2G determination of prothrombin time by ACL TOP, Instrumentation Laboratory, 11/2014.

Performing Laboratory

Barnes-Jewish Hospital 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 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:

24 hours at 2° C to 24° C
Additional Information: If the patient is a hospital patient and the hematocrit is >55%, call Barnes-Jewish Hospital Hematology Laboratory at 314-362-5203 for instructions.

Network Reference Lab Note:

Christian: Send specimen to BJH poured off at ambient temperature with Microbiology run.  Stability is 4 hours ambient.

Specimen Transport Temperature

Ambient/Refrigerate NO/Frozen NO

Reference Values

PT
9.7 - 13.0 seconds


INR
0.90 - 1.20

Physician alert value (automatic call-back): >5.0 INR

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

85610-PT

85611-PT fractionation

Additional Information

For BJH Laboratory Use Only

Analyte Stability:

24 hours at 2° C to 24° C


Laboratory Processing Instructions:

Test performed in BJH Core Lab.

LOINC Code Information

Name LOINC Code
PT 5902-2
INR 6301-6
PT 50/50 Mix 5956-8