Eurofins Biomnis code

PS

Synonyms

• Protein S anticoagulant activity
• protein S
• Protein S activity
• PS activity

Clinic significance

Protein S (PS) acts as a cofactor of Protein C to accelerate inactivation of the activated forms of Factors V and VIII. It is a vitamin K-dependent protein synthesized in the liver which circulates in either a free, functional form (40%) or in an inactive form in which it is bound to C4 binding protein (60%). The main purpose of this test is to detect congenital deficiency. Congenital PS deficiency is an autosomal dominant trait and both qualitative and quantitative deficiency is associated with recurrent venous thrombosis. Acquired PS deficiency (i.e. a loss of activity) is associated with liver disease, diabetes and inflammation (which entails elevated levels of C4 binding protein) or it can be induced by vitamin K antagonists and other drugs (L-asparaginase and oral contraceptives). This test should not be performed within one month of an episode of thrombosis or vitamin K antagonist treatment.This test is used to confirm or investigate PS deficiency.

Prenalytics

• 2 mL
• Citrated Plasma
• FROZEN

Further information

• PC and PS are vitamin K dependant and testing must be perform well after any AVK treatment (1 month)
• It is advisable to send us a frozen and centrifuged citrate sample in compliance with the GFHT pre-analytical recommendations.
• Enclose the specific clinical information form (R5-INTGB : Haemostasis)
• Attach the clinical information concerning the patient (significant inflammation, pregnancy, family history, etc.) and the clinical context (bleeding, thrombosis, preoperative assessment, etc.)
• Do not assay in the event of ongoing treatment with a direct-acting oral anticoagulant (XARELTO, ELIQUIS, PRADAXA).
• If activity low, we perform PSLI/Free protein S- antigen
• The assay should be performed after a 5-day discontinuation of the ODA treatment

Documents to download

• Specific clinical information form (R5-INTGB)

Methodology

Chronometric method

Turnaround time

2 days