Veripath Test Directory

Epic Test Name Prothrombin Time and INR
Synonyms PT/INR
Prothrombin Time, PT
Description The prothrombin time test (PT) is a global screening test with three major applications. These include 1) detection of FVII deficiency of the extrinsic coagulation pathway or common pathway (FII, V and/or X) indicative of hereditary or acquired bleeding disorder, liver disease or vitamin K deficiency; 2) monitoring test for oral warfarin therapy; and 3) assay for specific extrinsic and common pathway coagulation factors.
Specimen Requirements 
Container Light blue (3.2% sodium citrate) collection tube
Specimen Type Blood
Preferred Collection Volume 3 mL
Minimum Collection Volume Adult: 2 mL, Neonates : 2 mL
Collection Instructions When drawing specimens for coagulation testing, always draw a "pilot" tube (7-10ml plain red top tube), completely filled. This removes tissue fluid contamination. Samples should be obtained from peripheral vein wheneever possible. If drawn from indwelling catheter, the line should be flushed with 15mL of saline. After irrigation, a "pilot" tube should be drawn and discarded.
Specimen Handling In-house patients, transport at room temperature.
Out-side client, follow collection instructions and the steps below:
1. Spin light blue top tube. Remove plasma avoiding platelet/buffy coat layer. Spin plasma again to remove top portion of plasma ans place 1mL of PLATELET-POOR PLASMA in plastic tube. (Glass tube unacceptable). Double-centrifugation is critical for accurate results as platelet contamination may cause erroneous results.
2. Plasma must be frozen within 4 hours of collection. CRITICAL WARNING: Specimens must remain frozen until ready to test. Submit separate aliquots when multiple tests are ordered on the same patient specimen.
Rejection Criteria Hemolysis, clotted, short sample, thawed, contaminated with heparin, >24 hrs old.
Methodology Clotting based assay
Reference Range PT 9.8 - 12.5 seconds; INR 0.9 -1.3
CPT Code(s) 85610
Department Hemostasis/Coagulation
Contact Information Hemostasis Lab; 214-633-4959 Customer Service: 214-633-0400, Toll Free 1-877-887-8136.
Turn Around TimeIn-house; 2HRs, Outside Clients; 1 Day.
Performed Sunday - Saturday
Performed by Hemostasis Lab
Updated/Reviewed 07/25/2016