Protein S Activity

Protein S, PS
Core Laboratory & Transfusion Medicine
Hematology
Blood
PS2

MSH Coagulation requisition form (MS 520)
Protein S, a vitamin K-dependent plasma protein, synthesized predominantly within the liver, is the cofactor of activated protein C (protein Ca). It stimulates the proteolytic inactivation of Factor Va and Factor VIIIa by protein Ca, thereby stimulating its coagulation-inhibiting effect. A diminished protein S activity increases the thromboembolic risk.
Plasma (3.2% Na Citrate)
Full draw
Light Blue citrate tube
Collection Containers – Tube Types
Adult: 2.7 mL
Pediatric Micro tube: 1 mL
Send whole blood sample(s) at room temperature as soon as possible.
If specimens cannot be shipped immediately, centrifuge and separate plasma within 1 hour of collection, send frozen plasma on dry ice
8 hrs at Room Temperature, Freezer: 6 months at -70ºC or below.
Automated Coagulation Analyzer
Test may be requested at any time. Samples are aliquotted and frozen. The assay is run in batches.
Special arrangements made with Lab
1-4 weeks
0.59 – 1.26 U/mL In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.
416-586-4800 Extension 4688
Must indicate anticoagulant status