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