PT (Prothrombin Time)

SIM

20590 

CPT

85610 

Synonyms

Prothrombin time;  INR 

Specimen Type

Sodium Citrate Plasma 

Container

4.5 ml Sodium Citrate 3.2% Blue stopper tube

Collection Instructions

None

Volume

4 ml plasma 
Min: 2.0 ml 

Additional Information

Hemolysis does not effect this assay.

Patient Preparation

none

Specimen Processing Instructions

An individual test for PT can be sent room temp

*If a PT and PTT are order together, please follow the PPP(Platelet Poor Plasma) procedure as follows; Centrifuge at 3380 rpm’s (±100) for 5 minutes. Remove the plasma without disturbing the cellular layer. Then centrifuge the removed plasma again at 3380 rpm's (±100) for 5 minutes. Remove the platelet poor plasma to a final transfer tube. 

Transport Requirements

Room Temperature (Whole Blood)

Frozen (Platelet Poor Plasma)

DO NOT REFRIGERATE 

Specimen Stability

Room Temperature Plasma: 24 hours

Room Temperature Whole Blood: 24 hours 

Frozen Platelet Poor Plasma: 14 days

Rejection Criteria

• Refrigerated 
• Clotted Sample 
• Insufficient volume

Reference Range

• INR = 2.0 – 3.0
• PT = 12.7 - 15.1 seconds  

Critical Value

INR = >4.5  

Test Includes

PT and INR 

Methodology

Electromagnetic mechanical clot detection system 

Testing Frequency

Daily, Monday - Sunday 

Reviewed By

Summer Brochu

Reviewed

Supplemental