Category
Coagulation
SubCategory
bleeding/ bleeding risk assessment
Abbreviations
PT/INR
Synonyms/Aliases
prothrombin time assay,
Test
profile/ panel (bundled tests)
Results
results ready 2-4 hours after receiving sample.
Method
Time to clot formation
Temp
room temperature (24 hours maximum stability), frozen (30 days)
Setup
All working Days
Pre-analytic Considerations
.
Component Parameters
INR, Test Time, ISI
Sample Requirements
Citrated whole blood/ plasma
Test Ordering Instructions
fill out test request form fully & legibly. fill out test request form fully & legibly. provide clinical history including whether the patient is on anticoagulants e.g. warfarin or has liver disease.
Container / Presavative
citrate (light blue top) vacutainer during sample collection.
Test Considerations
fill out test request form fully & legibly.
Patient Preparations
N/A
Sample Types
citrated whole blood / plasma
Sample Volume
during sample collection, fill up to the mark on the tube (do not "add up" samples collected in other tubes to reach the required volume). if submitting separated citrated plasma, the aliquot label should identify the sample type as citrated plasma & 1-2ml submitted.
Rejection Criteria
labeling issue (unlabeled/ mislabeled); missing request form; wrong sample type; insufficient sample; hemolyzed samples; underfilled tubes, clotted samples, lipemic samples.
Other Instructions
sample should be separated after collection for transport
Reference intervals
test and control values are provided with report
Clinical utility
monitor patients on unfractionated heparin (ufh) therapy. examine factor deficiency in the extrinsic & common coagulation cascade pathway
Test Limitations /Confounders
Underfilled tubes, incorrect handling will give rise to wrong results. Patients with high hematocrit >55% require specially prepared tubes for correct results to be obtained.