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HelpCatalog ID PSTF Protein S Antigen, Plasma
Reporting Name
Protein S Ag, PUseful For
Investigation of patients with a history of thrombosis
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PSF | Protein S Ag, Free, P | No | Yes |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PST | Protein S Ag, Total, P | No | No |
Testing Algorithm
If this test result is decreased, then total plasma protein S antigen will be performed at an additional charge.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Plasma Na CitCollect 1 full Light Blue top tube.
Specimen Required
Specimen Type: Platelet-poor plasma
Patient Preparation: Patient must not be receiving heparin or Coumadin. If the patient is being treated with Coumadin, this should be noted. Coumadin will lower protein S.
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vials
Specimen Volume: 1 mL in 2 plastic vials each containing 0.5 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 0.5 mL of plasma into 2 plastic vials, leaving 0.25 mL in the bottom of centrifuged vial.
4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally  -40° C or below.
5. Send specimens in the same shipping container.
Additional Information: A double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Special Instructions
Reference Values
TOTAL
Males: 80-160%
Females
<50 years: 70-160%
≥50 years: 80-160%
FREE
Males: 65-160%
Females
<50 years: 50-160%
≥50 years: 65-160%
Normal, full-term newborn infants or healthy premature infants may have decreased levels of total protein S (15-50%); but because of low levels of C4b-binding protein, free protein S may be normal or near the normal adult level (≥50%). Total protein S reaches adult levels by 90 to 180 days postnatal.*
*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing
Day(s) Performed
Monday through Friday
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
85306-Free
85305-Total (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PSTF | Protein S Ag, P | 87557-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| PSF | Protein S Ag, Free, P | 27821-8 |
Report Available
1 to 3 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Method Name
PSF, PST: Latex Immunoassay (LIA)
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.