Ordering Recommendation

Acceptable test for detecting protein S deficiency. Preferred test is Protein S Free, Antigen (0098894). Do not order if the individual has been on warfarin therapy in the previous 2-4 weeks.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Lt. blue (sodium citrate). Refer to Specimen Handling at aruplab.com for hemostasis/thrombosis specimen handling guidelines.

Specimen Preparation

Transfer 1.5 mL platelet-poor plasma to an ARUP Standard Transport Tube. (Min: 1 mL)

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Serum. EDTA plasma, clotted or hemolyzed specimens.


Ambient: 4 hours; Refrigerated: Unacceptable; Frozen at -20°C: 3 months, at -70°C: 6 months


Electromagnetic Mechanical Clot Detection




1-2 days

Reference Interval

1-89 days: 15-55%
90-179 days: 35-92%
180-364 days: 45-115%
1-5 years: 62-120%
6 years:  62-130%
7-9 years: 66-140%
10-11 years: 65-139%
12-13 years: 72-139%
14-15 years: 68-145%
16-17 years: 77-167%
18 years and older: 66-143%


1-89 days: 15-55%
90-179 days: 35-92%
180-364 days: 45-115%
1-5 years: 62-120%
6 years:  62-130%
7-9 years: 62-151%
10-11 years: 65-142%
12-13 years: 70-140%
14-15 years: 55-145%
16-17 years: 51-147%
18 years and older: 57-131%

Interpretive Data

Patients on warfarin may have decreased functional protein S values. Patients should be off warfarin therapy for two weeks for accurate measurement of functional protein S. Artificially increased functional protein S values may be due to heparin therapy or the presence of direct thrombin inhibitors or factor Xa inhibitors.

Compliance Category



Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0030114 Protein S Functional 27822-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Functional Protein S
  • Protein S Activity, Plasma
Protein S, Functional