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Test Code SFX Protein S Activity, Plasma


Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: Patient must not be receiving Coumadin.

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze specimen immediately (no longer than 4 hours after collection) below -40° C.


Useful For

Second-order testing for diagnosis of congenital or acquired protein S deficiency, ie, as an adjunct to initial testing based on results of protein S antigen assay (free protein S antigen, with or without total protein S antigen assay)

 

Evaluating patients with a history of venous thromboembolism

Method Name

Optical Clot-Based

Reporting Name

Protein S Activity, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reference Values

Males: 65-150%

Females

<50 years: 50-150%

≥50 years: 65-150%

Newborn infants have normal or near-normal free protein S antigen (≥50%), although total protein S antigen is usually below the adult reference range. There are insufficient data concerning protein S activity in normal neonates, infants, and children; but normal or near-normal activity (≥50%) probably is present by age 3 to 6 months.

Interpretation

In type I and type III congenital deficiency, free protein S antigen is decreased, and protein S functional activity is similarly decreased. In type II congenital (dysfunctional) protein S deficiency, total and free protein S antigen levels are normal, but functional activity is decreased.

 

Patients with acquired free protein S deficiency associated with inflammation-related increase of C4b-binding protein typically have decreased free protein S antigen and protein S activity with normal (or elevated) total protein S antigen. Acquired protein S deficiency is of uncertain clinical hemostatic significance and is associated with a variety of conditions.

 

Elevated protein S levels are of uncertain clinical significance.

Clinical Reference

1. Borgel D, Gandrille S, Aiach M: Protein S deficiency. Thromb Haemost. 1997 Jul;78(1):351-356

2. Faioni EM: Protein S activity. In: Laboratory Techniques in Thrombosis-A Manual. 2nd ed. Kluwer Academic Publishers; 1999:153-161

3. De Stefano V, Finazzi G, Mannucci PM: Inherited thrombophilia: pathogenesis, clinical syndromes, and management. Blood. 1996 May 1;87(9):3531-3544

4. Zoller B, Garcia de Frutos P, Dahlback B: Evaluation of the relationship between protein S and C4b-binding protein isoforms in hereditary protein S deficiency demonstrating type I and type III deficiencies to be phenotypic variants of the same genetic disease. Blood. 1995 Jun 15;85(12):3524-3531

5. Grandrille S, Borgel D, Ireland H, et al: Protein S deficiency: a database of mutations. For the Plasma Coagulation Inhibitors Subcommittee of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. Thromb Haemost. 1997 Jun;77(6):1201-1214

6. Goodwin AJ, Rosendaal FR, Kottke-Marchant K, Bovill EG: A review of the technical, diagnostic, and epidemiologic considerations for protein S assays. Arch Pathol Lab Med. 2002 Nov;126(11):1349-1366

7.  Yohe S, Olson J: Thrombophilia: assays and interpretation. In: Kottke-Marchant Wiley K, ed. Laboratory Hematology Practice. Blackwell Publishing; 2012: 38:492-508

Day(s) Performed

Monday through Friday

Report Available

1 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

85306

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SFX Protein S Activity, P 27822-6

 

Result ID Test Result Name Result LOINC Value
SFX Protein S Activity, P 27822-6

Forms

If not ordering electronically, complete, print, and send an Coagulation Test Request (T753) with the specimen.