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Epic Code LAB320 PT/INR

Important Note

There is currently a nationwide shortage of this tube. Please take steps to ensure specimen integrity to reduce recollection. Specimen Tube Shortage (link)

  • Specimen tube must be full.
  • The ratio of blood to anticoagulant is critical.
  • Increased or decreased volumes of anticoagulant will cause erroneous results.

Test Name Alias

Protime with INR | PT with INR | 8434 | PTINR | Prothrombin Time | International Normalized Ratio

Interface Order Alias


Ordering Instructions

If PT is drawn in conjunction with APTT use APTT specimen requirements for handling instructions.

Icons & Photos

Sodium Citrate tubes

Collection Instructions

Specimen Collection: Blood


Container(s): 3.2% Na Citrate Tube (blue top)

Preferred Volume to Collect: 2.7 mL (full 2.7 ml Na Citrate blue tube)

Minimum Volume to Collect: 1.8 mL (full 1.8 ml Na Citrate blue white tube)

Capillary collect ok: No

Microtainer acceptable: No


Collection Instructions:


Processing Instructions (Laboratory, Outpatient or Off-site collection)

  • Processed Specimen: Platelet Poor Plasma
  • Centrifuge/Spin: Yes
  • Aliquot: Yes
  • Processing Instructions:
    • Detailed instructions (link): Preparing Platelet Poor Plasma
    • Separate plasma into 2 - 3 aliquots, minimum of 0.5 mL each.
    • Freeze aliquots in plastic transport tubes immediately.
  • Transport Temperature:

    • Ambient - up to 24 hours in whole blood state (unspun)
    • Frozen - plasma only >24 hours

Rejection Criteria

  • Hemolysis
  • Specimen has been thawed

Specimen Stability

Ambient: 24 hours (unspun)

Frozen: 2 months (aliquoted) 

Laboratory Retention: 24 hours

Reflex Information

Link: Mandatory reflex approved by MEC

Test Frequency

Available 24 hours, usual TAT 1 day.

Reference Range


  • 9.5 - 12.0 seconds 



  • 0.9 - 1.2 *INR value is clinically relevant only when patient is on warfarin
  • Low Intensity anticoagulation theraputic range: 2.0-3.0
  • High Intensity anticoagulation therapeutic range: 2.5-3.5


Laboratory Critical Values Table

Performing Department


Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI

Corewell Health Laboratories West:
Corewell Health Big Rapids Laboratory, Big Rapids, MI
Corewell Health Blodgett Laboratory, Grand Rapids, MI
Corewell Health Gerber Laboratory, Fremont, MI
Corewell Health Kelsey Laboratory, Lakeview, MI
Corewell Health Ludington Laboratory, Ludington, MI
Corewell Health Pennock Laboratory, Hastings, MI
Corewell Health Reed City Laboratory, Reed City, MI
Corewell Health Greenville Laboratory, Greenville, MI
Corewell Health Zeeland Laboratory, Zeeland, MI


Prothrombin clot-based assay



CDM Code


Epic Test ID



PT: 5902-2

INR: 6301-6

Mayo Access Code


Reviewed Date