Test Code LAB320 Protime (PT), Blood
Reporting Title
Protime
Methodology
Diagnostica Stago Inc. STA®-Neoplastine CL Plus
Used as a screening test for coagulation abnormalities including extrinsic coagulation factors, and for monitoring oral anticoagulant therapy.
Performing Laboratory
OhioHealth Laboratory Services-RMH, GMC, DNH, DMH, MGH, GMH, HMH, GCMH, DHC, WECC, PMH, MH, SH, BH and OBH Core Laboratories.
Specimen Requirements
Whole blood unspun specimen must arrive within 48 hours of draw.
Draw a full, light blue-top (citrate) tube; and send citrated whole blood. Invert several times to mix blood. Do not refrigerate.
Note: Gross hemolysis, icterus, and lipemia may also affect results.
Outpatients/Outreach Clients (when testing is not able to be performed on whole blood within 48 hours, send frozen plasma)
Plasma-Frozen
Draw a full, light blue-top (citrate) tube. Spin down, remove plasma, spin plasma again, and place 1 mL of citrated platelet-poor plasma into a plastic vial. (Glass vial is not acceptable.) Pour-off vial should be no more than 2/3 full. Send specimen frozen.
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Unspun whole blood | Room Temperature | 48 hours |
Spun, capped whole blood | Room temperature | 8 hours |
Frozen plasma | stable |
Specimen Transport Temperature
Ambient OK
Refrigerate NO
Frozen OK
Reference Values
PT
11.8-14.3 seconds
INTERNATIONAL NORMALIZED RATIO (INR)
0.8-1.1
During the induction phase of oral anticoagulation, the INR may not reflect the anticoagulation status of the patient.
THERAPEUTIC RANGES FOR INR
Most clinical situations: 2.0-3.0
Mechanical prosthetic valve: 2.5-3.5
Critical value: >5.0
Alerting category: Always called within 1 hour
Note: PT results may be affected by a number of commonly administered drugs. These should be considered when unusual or unexpected results are obtained. Unexpected abnormal results should be followed by further coagulation studies to determine the source of the abnormality.
Day(s) Test Set Up
Monday through Sunday; Continuously
Test Classification and CPT Coding
85610