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Test Code LAB320 Prothrombin Time (PT) with INR

Specimen Requirement

2.7 mL whole blood Sodium Citrate (blue-top) tube

 

1.0 mL Sodium Citrate plasma

Specimen Minimum Volume

1.8 mL whole blood Sodium Citrate (blue-top) tube

 

0.5 mL Sodium Citrate plasma

Specimen Stability

Whole blood: 24 hours at room temperature

 

Plasma: 2 weeks at -20° C.

Testing Schedule

Daily

Reference Range

PT:

  • 9.3 – 12.3 seconds

 

INR:

  • Normal: 0.9 – 1.2
  • Therapeutic: 2.0 – 3.0
  • High Risk: 2.5 – 3.5

Testing Department

Hematology/Coagulation

Method

Scattered light clot detection

CPT Code

85610

Additional Testing Locations

This test is also performed daily at the following Altru Clinics:

  • Crookston
  • Devils Lake
  • East Grand Forks
  • Family Medicine Residency
  • Altru Professional Center Laboratory

Please contact appropriate lab location for specific test information, as methodology varies by site.