Laboratory Medicine Program

Partial Thromboplastin Time, Lupus-sensitive (LsPTT)

Clinical Decription:
The LsPTT is included in a panel of tests designed to detect the presence of an antiphospholipid antibody. An activated partial thromboplastin reagent with increased sensitivity to lupus-like inhibitors is used in the determination of the activated partial thromboplastin time. As a global screening procedure, the PTT is used primarily to evaluate coagulation abnormalities in the intrinsic pathway, as well as detect severe functional deficiencies in factors II, V, X. or fibrinogen.

Method: Optical Clot Detection; Siemens Sysmex CS-5100

Component Tests Used: dilute Russell Viper Venom Time, Lupus-sensitive PTT, Anti-cardiolipin Antibodies

Reference Ranges Used:
Medical Interpretation is provided

Specimen Type: Citrated plasma
Collected In: 3.2% Sodium Citrate
Volume: 3 x 1.0 mL (minimum: 3 x 1.0 mL)

Shipping: Send frozen on dry ice.

Special Instructions: Patient should be fasting, if possible. Anticoagulants should be held for a requisite amount of time prior to testing to ensure no anticoagulant effect on the plasma. 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. Patients receiving a Direct Thrombin Inhibitor such as Dabigatran, cannot be tested for the Antiphospholipid Antibody as the anticoagulant interferes with the clotting assays.

Testing Schedule(s): Weekly.

Turnaround Time: 10 Business days

For more information, call 416.340.5227 or 1.866.865.5227