Tests:Activated Partial Thromboplastin Time, Plasma

APTT is part of a coagulation screen

Overview
Department	Haematology
Test Code	TAPT
Synonyms	APTT PTT Activated Partial Thromboplastin Time Coagulation screen
Base Lab Availability	Monday - Sunday, testing routinely available out of hours
Hawera Lab Availability	Monday - Friday 8 am - 5pm
Turnaround Time	0.5 – 4 hrs
Stability – Add test	12 hours at room temperature   2 hours for Unfractionated heparin monitoring
Specimen Requirements
Specimen	Plasma
Preferred	2.7mL Na citrate Blue-Top
Acceptable
Unacceptable	Clotted specimen Under or overfilled Moderately haemolysed Specimen older than 12 hours Unfractionated heparin monitoring older than 2 hours
Specimen Transportation	Room temperature
Paediatric Requirements	1 mL Na citrate Blue-Top
Aliquot Requirements
Sample
Preferred Volume
Minimum Volume
Aliquot Transportation
Clinical Information
Reference Intervals	Reference Range - 24-38 seconds   Paediatric range - contact laboratory   Therapeutic range -(unfractionated heparin) 50-80 seconds
Test Method	Mechanical clot detection performed on Stago Compact Max2 Analyser
Advanced Notice	Not required
Patient Preparation	Not required
Comments
Please give all clinical details, including all medication.   If the patient is on unfractionated heparin, request APTT only.     Please indicate if patient is on low molecular weight heparin (Clexane).

Owner	Craig Mabbett (Mabbett1)
Last reviewed	21.11.2025
Next review	21.11.2026 (OK)