Test Code: APTT Preferred Name Activated partial thromboplastin time

45 minutes
As required
2 hours
Medicare Item
4 hours

Test Tubes

ImageSpecimen TypeSpecimen VolumeTube Type
Blood (adult)2.7 mLSodium Citrate 2.7 mL (Solid Pale Blue Top)
Blood (paediatric)1.8 mLSodium Citrate 1.8 mL Paed (Clear/Pale Blue Inner)
Blood (neonatal)1.0mlSodium Citrate 1.0 mL Neonate (Pale Blue Top)


Accurate filling of specimen tube essential.
All collections that include Coagulation testing must be sent to the laboratory in a BLUE specimen bag.
Specimens must be stored and transported to the laboratory at RT. (Maximum delay to testing laboratory must not exceed 4hrs)
If monitoring heparin therapy, testing should be performed within 1 hour of collection.
Please ask the patient what anticoagulants they are on and the dose, record on request form


The APTT assay is a universally accepted screening procedure used to detect abnormalities in the intrinsic coagulation system, including factor deficiencies and inhibitors including Lupus Anticoagulant. Additionally it is used to monitor heparin therapy. A normal aPTT does not necessarily exclude von Willebrand's disease, as the test tends to be prolonged only when F VIII levels fall below ~35%. An unexpected prolonged aPTT in the absence of a bleeding tendency may point to F XII deficiency or a lupus anticoagulant

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