bleeding/ bleeding risk assessment




prothrombin time assay,


profile/ panel (bundled tests)


results ready 2-4 hours after receiving sample.


Time to clot formation


room temperature (24 hours maximum stability), frozen (30 days)


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


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.