1041

Protein S Activity

Order Code: 1041 Get Requisition Form

Test Information

This test provides the activity level of the blood coagulation factor, Protein S. This protein is one of the regulatory proteins in the blood clotting cascade.

Also Known As

PS
PS Activity

Test Type

Functional/Serologic Test

Sample Notes

Citrated Plasma (light blue top)

Requested Volume

0.5 ml

Minimum / Pediatric Volume

0.3 ml

Additional Sample Information

Protein S activity is measured by a prothrombin-time-based clotting method. Patients should be off warfarin for at least 4 weeks before drawing a sample. The assay kit manufacturer has demonstrated the assay to be unaffected by levels of unfractionated heparin or low molecular weight heparin up to 2 IU/mL, but the results may be artifactually elevated in samples containing dabigatran or rivaroxaban. Platelet contamination of plasma samples causes an under-recovery of Protein S level, and proper sample preparation is required. Age and gender specific reference intervals are used.