Prothrombin Time (Abnormals reflex to 1:1 mix)

Profile or Test Panel
Abnormal PT or aPTT Reflexive Evaluation Profile
Additional assays will be performed as indicated.
Intrinsic Factor Evaluation Profile
Extrinsic Factor (abnormal PT) Evaluation Profile
Bleeding Diathesis with a Normal aPTT/PT Profile
DIC Panel
Factor Inhibitor non-Factor VIII Profile
Fibrinolysis Evaluation Profile
  • Abnormal PT or aPTT Reflexive Evaluation Profile
    (See panel above “Abnormal PT or aPTT Reflexive Evaluation Profile” for reference.)
  • Antiplasmin
  • D-Dimer quantitative
  • FDP
Lupus Anticoagulant Profile
Abnormal result reflexes to the following tests as indicated.
Method Clottable
Test Information The prothrombin time (PT) is a kinetic screening test performed by adding a sensitive tissue thromboplastin reagent and calcium chloride to plasma using an automated method. The PT assesses the extrinsic pathway of coagulation that includes factors VII, X, prothrombin, and fibrinogen. Prolongation of the PT can be caused by factor deficiency or factor inhibitor. The PT is more sensitive than the APTT for liver disease or the presence of warfarin, rivaroxaban or edoxaban. The PT is less sensitive than the PTT to the presence of heparin, lupus anticoagulants, or dabigatran. Improper sample collection or processing can result in shortening or prolongation of the PT.
Additional Test Information Normal ranges are included on testing report and can be made available upon request.
Sample Requirements Whole Blood: 3.2% sodium citrated (blue top) OR
frozen plasma
Requested Volume Two 5 ml 3.2% sodium citrated (blue top) tubes as whole blood OR
frozen plasma in 4 X 1mL aliquots in plastic tubes
Sample Information Whole blood is preferred for testing, but if it is not possible to send whole blood tubes TO ARRIVE HERE WITHIN 2 HOURS of collection, then send frozen plasma. To prepare plasma, centrifuge blue top tubes at 1500g for 15 minutes and remove the plasma and centrifuge a second time at 1500g for an additional 15 minutes. Aliquot approximately 1 ml of plasma into 4 plastic tubes, and freeze.
Shipping Information Whole Blood: Send at ambient temperature (18-25°C) and must be received within the lab in less than or equal to 2 hours after collection.

Frozen Plasma: Send on dry ice

Send samples to:
Bloodworks Northwest
Attn: Hemostasis Laboratory
921 Terry Ave
Seattle, WA 98104

For additional information, please see Ordering Information

Requisition Form RFT- Hemostasis Reference Laboratory
Transaction Code 3200-04
CPT Codes 85610
Test Schedule Monday-Friday
Turn around Time (analytic time) 3 Business Days
Report/Results Fax number required to receive report

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