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PT With INR

Important Note

Direct oral anticoagulants which inhibit Factor Xa (rivaroxaban, apixaban, edoxaban) positively interfere with the PT/INR (e.g. anti-Xa DOACs prescribed concurrently with warfarin/Coumadin can produce a falsely elevated PT/INR).

Performing Lab(s)

Memorial-Belleville & Memorial-Shiloh

Methodology

STA

Specimen Requirement (s)

Specimen:  whole blood

Type: Container/Tube:  blue (sodium citrate) tube

Specimen Volume: full tube

Specimen Minimum Volume:  NA

 

Collection Instructions: Deliver to lab immediately.

Lab instructions: Testing must be performed within 24 hours of collection.

Unacceptable Conditions

  • Avoid hemolysis 
  • Short draws 
  • clotted specimens 

Day(s)/Shift(s) Test Set Up and Turnaround Time

Sunday through Saturday

Hours: 24 hours

 

Turnaround Time:

STAT: 45 minutes

Routine: less than 8 hours from receipt.

Transport and Stability

Transport temperature: Ambient to lab

Reference Values

PT

Reference Values

Critical High

12 .0– 14.6 sec

NA

 

INR

Reference Values

Critical High

0.8 – 1.2

≥ 5

CPT/LOINC Codes

85610

Interpretive Data

Interpretive data - INR

Oral anticoagulant therapeutic ranges:

Venous thromboembolism prophylaxis or treatment: 2.0-3.0

CARDIOLOGY

Standard range: 2.0-3.0

High-intensity range: 2.5-3.5

Refer to indication-specific guidelines for appropriate target ranges for prosthetic heart valve replacement.

Current interpretive data was last revised on 12/03/2019.