Protein S Activity PSACT

Synonyms

Allscripts (AEHR) Order Name

Protein S Free Activity Assay

Sunrise Clinical Manager (SCM) Order Name

Protein S Free Activity Assay

Clinical Info

Confirmation and characterization of protein S (PS) congenital deficiency
 
 

Specimen Type

Blood

Container

Blue Top Tube

Collection Instructions

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.

Transport Instructions

Frozen

Specimen 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.

Methodology

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.

Days Performed

Performing Laboratory

LabCorp

CPT

85306
 
LOINC Code:  27822-6

PDM

5608160

Result Interpretation

  63-140 %
 
The presence of heparin or lupus anticoagulants leads to overestimation of PS. aPC resistance due to factor V_Leiden mutation or some other cause can falsely lower measured PS activity levels.

Forms