Protein S Free Activity Assay

Protein S Free Activity Assay

Confirmation and characterization of protein S (PS) congenital deficiency
 
 

Blood

Blue Top Tube

Container/ Tube: Blue-top (sodium citrate) tube Specimen: 1 mL Plasma (minimum 0.5 mL) Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube. Transfer the plasma into aliquot tube. Transport Temperature: Frozen Stability: 7 Days Frozen Patient Preparation: Avoid warfarin (Coumadin®) therapy for two weeks and heparin therapy for two days prior to the test. Do not draw from an arm with a heparin lock or heparinized catheter.

Frozen

7 Days Frozen Patient Preparation: Avoid warfarin (Coumadin®) therapy for two weeks and heparin therapy for two days prior to the test. Do not draw from an arm with a heparin lock or heparinized catheter.

The patient plasma is added to PS-depleted normal plasma with normal levels of all factors but PS. The mixture is supplemented with excess aPC and factor V is then added. The extent of prolongation of the time to clot formation after calcium chloride is added is proportional to plasma PS activity.

LabCorp

85306
 
LOINC Code:  27822-6

5608160