ACTIVATED PARTIAL THROMBOPLASTIN TIME (aPTT)

Sub Category

bleeding/ bleeding risk assessment

Synonyms/Aliases

partial Thromboplastin time, Kaolin Cephalin clotting time

Abbreviations

APTT, PTT, KCCT

^Test

Indivudual Test

^Results

2-4 hours after receiving sample.

^Temp

room temperature (4 hours stability), frozen plasma (30 days)

^Method

time to clot formation

^Setup

All working days

Component / Parameters

.N / A

Pre-analytic Considerations

N / A

Sample Requirements

Citrated whole blood/ plasma

Patient Preparations

Citrated whole blood/ plasma

Sample Type

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.

Test Ordering Instructions

fill out test request form fully & legibly. provide clinical history including whether the patient is on anticoagulants e.g. unfractionated heparin (ufh) or has liver disease.

Container Presavative

Citrate(LIGHT BLUE TOP) Vacutainer

Rejection Criteria

labeling issue (unlabeled/ mislabeled); missing request form; wrong sample type; insufficient sample; hemolyzed samples; underfilled tubes, clotted samples, lipemic samples; frozen whole blood samples.

Other Instructions

Send citrated whole blood at room temperature; alternatively send separated plasma at room temperature (must be tested within 4 hours of collection) or frozen plasma. Should not be haemolyzed or clotted. Samples ?4 hours old received at room temperature are rejected; special tubes should be prepared for clients with hematocrit ?55% 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 intrinsic & common coagulation cascade pathway

Test Limitations /Confounders

monitor patients on unfractionated heparin (UFH) therapy. examine factor deficiency in the intrinsic & common coagulation cascade pathway