Laboratory Medicine Program

Partial Thromboplastin Time, activated (aPTT)
(PTT)

Clinical Decription:
The aPTT is used to assess deficiencies or inhibitors of the intrinsic pathway factors (Factors XII, XI, IX, VIII) and common pathway factors (Factors X, V, II, fibrinogen).

Method: Optical clot detection; Siemens Sysmex CS-5100

Component Tests Used: n/a

Reference Ranges Used:
23.0 - 30.0 sec

Specimen Type: Citrated plasma
Collected In: 3.2% Sodium Citrate
Volume: 1.0 mL (minimum: 1.0 mL)

Shipping: frozen plasma

Special Instructions: Patient should be fasting, if possible. The specimen must be centrifuged and plasma separated within 1 hour of collection. The specimen must be double-centrifuged to obtain a platelet-poor plasma specimen (Plt <10x10E9/L): 1. Immediately centrifuge specimen at 1500xG for 10 minutes. 2. Separate the plasma from the platelet/buffy coat and transfer into a clean plastic tube. 3. Centrifuge the separated plasma at 1500xG for 10 minutes. 4. Transfer 1.0 to 2.0 mL of the double-centrifuged plasma into a clean plastic tube, leaving approx. 200 uL for discard. 5. Freeze plasma aliquot immediately for storage. Maintain frozen for shipping and handling.

Testing Schedule(s): Daily.

Turnaround Time: 1 day

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For more information, call 416.340.5227 or 1.866.865.5227

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