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Test Code 8434 PT/INR (Prothrombin Time)

Important Note

Test subject to Medicare National Coverage Determination (NCD) 190.17 PT TESTING

See Medical Necessity on Sidebar

Includes Prothrombin Time (PT) and International Normalized Ratio (INR).

Purpose

Evaluation of the extrinsic coagulation system; aid in screening for congenital and acquired deficiencies of factors II, V, VII, X, and fibrinogen. This test is used clinically for the therapeutic monitoring of warfarin (Coumadin) anticoagulant therapy.

 

Performing Laboratory

Copley Hospital

 

Methodology

Photo-Optical

 

Specimen Requirements

Specimen Type: Blood (Plasma)

Container/Tube: Light-Blue Tube

Specimen Volume: Full Tube

Specimen Minimum Volume: Full Tube

 

Collection Instructions: 

1. If using a butterfly collection set up, draw a waste tube

     first before the coagulation tube.

2. Label specimen with patient’s full name, date of birth,

    date & time of collection, and person collecting.

3. Keep specimen at room temperature during transport.

 

Reference Values

Normal:               PT: 9.3 - 11.4 Seconds               INR: 2.00 - 3.00

Critical:                                                                      INR: > 3.5

 

Stability

Room Temperature: 24 Hours

 

Day(s) Performed

Daily

Available STAT

Analytical Time: 1 Day

 

Aliases

PT/INR (Prothrombin Time)

PT/INR

Prothrombin Time

 

Test Classification and CPT Coding

85610