Protein S Functional (free)  Email this article           Printer friendly page


Primary Name Protein S Functional
Synonym Protein S activity
Synonym --
Contraction PS
Contraction --
Contraction --
UAB Procedure Number 2500380
CPT Code 85306
Specimen Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill.

Specimen Management Centrifuge blue-stopper tube within one (1) hour of collection, separate plasma and test or quick-freeze at -70°C.
Specimen Accepted Daily including weekends
Test Performed Two days a week
Available Stat? No
Description When the functional PS level is consistently decreased, the patient may have a congenital deficiency. Chronic PS deficiency confers a 2- to 11-fold risk of venous thrombosis. Acquired PS deficiency occurs in a number of inflammatory conditions, during pregnancy, following a thrombotic episode, and in liver disease. Protein S production is decreased during Coumadin (warfarin) therapy. The protein S assay should be ordered at least 10 days after a thrombotic event or after termination of Coumadin therapy. When the INR is >1.7 the protein S order is canceled.
Reference Interval 65%-140%
Follow-up Test If the functional PS assay indicates a deficiency, total and free protein S antigen assays and the C4B binding protein immunoassay may be used to distinguish among qualitative and quantitative disorders.
These tests will be sent to a reference lab.
Associated With Venous thrombosis
Associated With Arterial thrombosis
© Copyright by the University of Alabama at Birmingham
Top of Page