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Laboratory Test Directory

Prothrombin Time

Components

Name Method Department Units
Prothrombin Time Clot detection
Core Lab, Coagulation sec

Battery Members

PT, INR (International Normalized Ratio)

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Preferred

Blue plastic tube (Citrate)

2.7 mL 2.7 mL
Alternate

Blue plastic tube (Citrate)

1.8 mL 1.8 mL
Stability

Room temperature - 24 hour(s)

Specimen Preparation

  • Do not centrifuge
  • Fill tubes to appropriate mark.
  • Mix by gentle inversion immediately after collection
  • Keep at room temperature
  • Transport to laboratory as soon as possible

Platelet poor plasma

Container Type Container Size Specimen Volume
Preferred

Blue plastic tube (Citrate)

2.7 mL 2.7 mL
Stability

Frozen - 2 week(s)

Alternate

Blue plastic tube (Citrate)

1.8 mL 1.8 mL
Stability

Frozen - 2 week(s)

Specimen Preparation

  • Fill tubes to appropriate mark.
  • Mix by gentle inversion immediately after collection
  • Centrifuge, remove plasma/serum and freeze
  • Plasma must be platelet free

Reasons for Rejection

  • Clotted specimen
  • Over or under filled tube
  • Gross hemolysis
  • Not received within specified time frame
  • Wrong collection tube
  • Capillary specimen

Comments

INR result can be used to monitor patients receiving Warfarin/Coumadin therapy. Indicate collection method on sample. Indicate if patient is receiving Coumadin (Warfarin). Centrifuge citrate tubes according to Lab policy, remove platelet-poor plasma, pool the plasma, aliquot and freeze. Send a minimum of two (2) aliquots of plasma.

 

To view Recommendations for Monitoring Anticoagulant Therapy click here.

CPT Code

  • 85610