Protein S Activity, Clot
General Information
Lab Name
Protein S Activity
Lab Code
PSCLOT
Epic Name
Protein S Activity
Description
Protein S activity is a clot-based quantitative assay to measure the functional protein S level for diagnosis of congenital or acquired protein S deficiency. Protein S activity is recommended if initial testing with Free Protein S Antigen (PSAGF) is decreased. Congenital protein S deficiency is characterized by recurrent thrombosis and the classification of the protein S deficiency is dependent upon the protein S antigen and activity levels. Protein S is a vitamin K-dependent protein. Patients on warfarin therapy may see a decrease in protein S activity due to the vitamin K antagonistic effect of the drug. Protein S activity may also be decreased in the setting of acute phase responses, pregnancy, cirrhosis, L-asparaginase treatment, use of oral contraceptives, DIC or acute thrombotic event.
Recommend Free Protein S Antigen (PSAGF) assay if the patient is taking direct oral anticoagulants.
Outside clients should fill and submit Coagulation Patient Clinical History Form: Coagulation Patient Clinical History Form
Synonyms
Protein S-Clot Based
Interpretation
Method
Stago Staclot Protein S Assay
Reference Range
Units: %
| Female | Male | ||
|---|---|---|---|
| Age | Range | Age | Range |
| 0-2m | 15-150 | 0-2m | 15-150 |
| 3m-5m | 35-150 | 3m-5m | 35-150 |
| 6m-11m | 47-150 | 6m-11m | 47-150 |
| 1y-5y | 49-150 | 1y-5y | 49-150 |
| 6y-9y | 58-150 | 6y-9y | 58-150 |
| 10y- | 55-150 | 10y- | 65-150 |
Effective date: 03/01/2010
Ref. Range Notes
Elevated Protein S is not associated with thrombosis or bleeding.
Interferences and Limitations
Patients on direct thrombin inhibitors such as bivalirudin (Angiomax), dabigatran (Pradaxa), argatroban (Novastan) or anti-Xa drugs such as rivaroxaban (Xarelto), apixaban (Eliquis) and edoxaban (Savaysa), may lead to an over-estimation of the protein S level with this assay. Recommend Free Protein S Antigen (PSAGF) assay if the patient is taking direct oral anticoagulants. This assay is not affected by heparin levels up to 1 IU/mL.
Ordering & Collection
Specimen Type
Collection
3 or 5 mL BLUE (CITRATE) tube
Forms & Requisitions
Outside clients should fill and submit Coagulation Patient Clinical History Form: Coagulation Patient Clinical History Form
Approval Required
Laboratory Medicine resident's approval is required for hospital inpatients and patients in Emergency Department.
Handling Instructions
The Laboratory MUST process specimen, within 4 hrs of blood collection.
Quantity
requested: entire sample
Processing
**Laboratory Medicine resident's approval is required for hospital inpatients and patients in Emergency Department.**
Approval is NOT required for hospital outpatients, clinic patients or outside clients. Note: If request simply states PROTEIN S, see PSAGF
UW-MT Instructions: Take specimen to UW-MT Coag lab for processing. Coag tech will freeze plasma sample for transport to HMC Coag.
HMC Instructions: Take specimen to HMC Coag lab for processing.
Outside Laboratory: Centrifuge for 10 minutes, remove plasma & re-spin plasma for another 10 minutes. Decant & Freeze plasma (minimum 1.0 mL) @ -20°C to -80°C. Send frozen on dry ice.
Performance
LIS Dept Code
Coagulation (COAG)
Performing Location(s)
| HMC |
Coagulation
206-520-4600 325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420 |
|---|
Frequency
Run on Thursday and reported by end of day.
Available STAT?
No
Billing & Coding
CPT codes
85306
LOINC
Interfaced Order Code
UOW1155
Interfaced Result Code
UOW1155