Pathology

Test & Collection Guide

Prothrombin Time

Ordering information:

Warfarinsied outpatients can use a "Rule 3 Exemption" request to allow multiple INR collections to be made using the one request form.

Please click here for a link to the Rule 3 Exemption Request Form
Please click here for a link to the Warfarin Dosing Referral Form

Alternate names:

DINR, INR, PT

Laboratory:

Coagulation

Test Code:

INR, DINR

Specimen types:

Plasma

Container types:

Sodium Citrate

Collection Instructions:

Transport specimen at Room Temperature to lab

Filled to label marker and mixed by inversion.

Patient Information - Warfarin Management-English
Patient Information - Warfarin Management-Greek
Patient Information - Warfarin Management-Simplified Chinese

Frequency:

Daily

Result Turnaround Time:

2 hours

Reference Interval:

Prothrombin Time is expressed as the International Normalised Ratio (INR)

0.8 - 1.2 INR

Prophylaxis for atrial fibrillation	2.0 - 3.0	INR
Treatment of deep vein thrombosis	2.0 - 3.0	INR
Tissue heart valve replacement	2.0 - 3.0	INR
Mechanical heart valve replacement	2.5 - 3.5	INR
Anti-phospholipid syndrome	2.0 - 3.0	INR

Laboratory Use Only

Storage Instructions:

Specimens for PT-INR assays centrifuged with plasma remaining on top of the cells in an unopened tube kept at room temperature may be tested within 24 hours from time of specimen collection.