Laboratory Medicine Program

Inhibitor Screen (Mixing Studies)
(1:1 Mix, 50/50 Mix)

Clinical Decription:
Mixing studies are performed to investigate the unexplained prolongation of either the PT or aPTT. Prolongation in the PT or aPTT are caused by factor deficiencies, endogenous inhibitors (specific or non-specific) or exogenous inhibitors such as heparin. Failure of a 50/50 mix to correct is indicative of an inhibitor while full correction indicates factor deficiencies. Further specific coagulation studies are usually indicated to further characterize these defects.

Method: Optical Clot Detection; Siemens Sysmex CS-5100

Component Tests Used: PT,aPTT, immediate mixing studies when required

Reference Ranges Used:
No inhibitor present

Specimen Type: Citrated plasma
Collected In: 3.2% Sodium Citrate
Volume: 2.0 mL (minimum: 2.0 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.

Testing Schedule(s): Daily.

Turnaround Time: 1 day

For more information, call 416.340.5227 or 1.866.865.5227