• A basic coagulation screening test for the assessment of congenital and acquired deficiencies of the extrinsic pathway (factors II, V, VII, X).
  • The Prothrombin time can be prolonged in certain clinical states, i.e. warfarin therapy, intestinal reabsorption disorders, liver failure, fibrinolysis and DIC
• To monitor warfarin therapy

 Lt blue Sodium citrate (Na Cit) - 2.7mL 

If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube.

Hematocrit-Anticoagulant adjustments

• Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical

Coag – tube fill guidelines

• If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube. Refer to the Collection container for instructions.
• Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting

Test must be run within 24 hours of collection.

Lt blue Sodium citrate (Na Cit) - 2.7mL tube

If the sample will not reach the AHL Central Laboratory within 24 hours:

1. Process Platelet Poor Plasma (P.P.P)

   Coag – how to prepare a specimen for special coagulation testing

2. Transfer plasma into an aliquot tube using a spot label "NaCit Plasma P.P.P" to label as platelet poor plasma
3. Freeze immediately

Microcentrifuge vial/tube in a Snap cap conical vial/tube and cap (Beaker sites)

Coagulation specimen transport vial/tube  (all other sites)

Whole blood:

Ambient - 24 hrs

Plasma:

Frozen (OK)

• Greiner tubes are not acceptable
• Improper labeling (unlabeled or mislabeled)
• Improper anticoagulant
• Improperly filled tube
• Hemolysis
• Clotted specimen
• Delay in transport
• Improper storage/transport temperature

Clot Based Assay

Protime: 10.6 - 12.4 seconds

INR:

0 - 28 days: > 1.3

>28 days:    > 6.0

Medical necessity