INNOVANCE Free PS Ag Assay
Easy, specific, and stable protein S antigen testing
The INNOVANCE® Free PS Ag assay is straightforward to use and easily fits into the laboratory routine. Meanwhile, the ISTH Guideline1 recognizes that free protein S antigen assays are the first-line diagnostic for protein S deficiency. The INNOVANCE Free PS Ag assay is a liquid latex reagent with high specificity for free protein S using two different antibodies that do not bind to protein S/C4b-binding protein complexes. In addition, this assay shows low interference with rheumatoid factors and heterophilic antibodies.
The liquid, truly ready-to-use reagent requires no additional mixing or standing time, so it is easy to handle without the wait on Siemens Healthineers hemostasis systems.
- The assay is economical to use, with superior once-opened stability of 8 weeks at 2–8°C.
- The assay provides high linearity and excellent precision over the entire measuring range of 10–150% of norm.
- The INNOVANCE Free PS Ag assay shows no major interferences, including interferences from rheumatoid factors and heterophilic antibodies.
The INNOVANCE Free PS Ag assay brings high precision, stability, and easy handling. It enables you to rely on protein S diagnostic testing.
Lead Scientist Hemostasis Assays
Lead Scientist Hemostasis Assays
With once-opened stability of 8 weeks, the INNOVANCE Free PS Ag assay offers convenient testing for any-sized lab.
No waiting time
Liquid, ready-to-use reagent requires no manual preparation or standing time
10-150% of norm
Onboard stability and within-device/lab CV (%) are indicated for use on the Sysmex® CS-2500 System. Assay claims may vary depending on system utilized. The values listed above are provided as examples only.
INNOVANCE Free PS Ag Assay Kit Components
The INNOVANCE Free PS Ag assay is a turbidimetric, latex-based assay that employs a liquid, ready-to-use reagent. The assay consists of three components and can be ordered as a kit.
INNOVANCE Free PS Ag Buffer
Ready-to-use liquid containing a heterophilic blocking reagent and preservatives.
Available on Siemens Healthineers and Sysmex Systems
For details on available assay applications and ordering information, download the hemostasis reagent portfolio catalogue.
Complete thrombophilia and protein S testing portfolio
The Siemens Healthineers INNOVANCE Free PS Ag and Protein S Ac assays support differentiation between type I and type II protein S deficiencies. Combined with other Siemens Healthineers thrombophilia assays, the INNOVANCE Free PS Ag assay completes your lab's thrombophilia testing portfolio. Now you can obtain a broad thrombophilia testing solution from a single, trusted supplier, streamlining your ordering and administration processes. Benefit from excellent result correlation across Siemens Healthineers hemostasis testing platforms.
About protein S
Protein S is a plasma protein produced in the liver. It is an anticoagulant, functioning as a cofactor for protein C-mediated inhibition of activated factor V and factor VIII. There are two forms of protein S in plasma: free protein S (the active form) and protein S bound to C4b-BP. Synthesis of protein S is vitamin K-dependent, and normal activity for protein S ranges from 60-130% of norm.
Protein S deficiency and venous thrombosis
Protein S deficiency is a risk factor for venous thrombosis. Therefore, protein S testing plays an important role in thrombophilia screening. Protein S deficiency may be congenital or acquired in many ways, including oral anticoagulation therapy, hepatic or kidney disorders, pregnancy, and oral contraceptives or estrogen therapy.
Protein S determination
Several methods currently exist for determination of protein S. Functional assays such as protein S Ac assays measure protein S activity. In contrast, immunoassays measure different types of protein S antigen. Free protein assays measure free protein S only, while total protein S assays measure both free and bound protein S antigen. According to latest guidelines, the initial assay for congenital PS deficiency should be the free PS antigen assay.
- Before testing for protein S deficiency, causes of acquired deficiencies and for interfering factors should be assessed. Testing for congenital protein S deficiency on patients with acquired conditions is recommended to be deferred.
- Protein S deficiency was classified into three phenotypes (type I, II, and III) by Bertina in 1991 (during the ISTH-SSC meeting).
- A free protein S Ag assay is recommended as the initial assay for congenital Protein S deficiency. A total Protein S Ag assay can be performed to differentiate between type I and type III deficiency but is recognized to provide little clinical information. Protein S activity testing in a patient with a normal free protein S Ag result may be useful in case of strong clinical suspicion, to identify Protein S type II deficiency. Protein S activity is measured with a protein S Ac assay, an activated protein C (APC)-cofactor activity test using the factor Xa-pathway. It uses Russell’s viper venom (RVV) as a factor X-activator by adding protein S-deficient plasma and APC.
- If an abnormal value is obtained, testing must be repeated after at least 4 weeks for confirmation.
- There are different types of protein S activity and antigen assays1,2 that generate different result levels. Samples from a given patient should always be measured with the same type of assay.
- The current protein S type II deficiency is an APC-cofactor deficiency. A deficiency in TFPIα-cofactor activity (single or pleiotropic with APC-cofactor) was recently described. To date, no cases of these subtypes have been reported. Moreover, its association with venous thromboembolism is not yet established.
Marlar RA, Gausman JN, Tsuda H, Rollins-Raval MA, Brinkman HJM. Recommendations for clinical laboratory testing for protein S deficiency: communication from the SSC of the ISTH. J Thromb Haemost. 2021;19:68-74. https://doi.org/10.1111/jth.15109
Brinkman HJM, Ahnström J, Castoldi E, Dahlbäck B, Marlar RA. Pleiotropic anti¬coagulant functions of protein S, consequences for the clinical laboratory: communication from the SSC of the ISTH. J Thromb Haemost. 2021;19:281-6. https://doi.org/10.1111/jth.15108
Not available for sale in the U.S. Product availability may vary from country to country and is subject to varying regulatory requirements.
Sysmex CN-3000 System refers to Automated Blood Coagulation Analyzer CN-3000. Sysmex CN-6000 System, CS-5100 System, CS-2500 System, and CA-660 System refer to Automated Blood Coagulation Analyzer CN-6000, -CS-5100, -CS-2500, and -CA-660 respectively.
Product availability may vary from country to country and is subject to varying regulatory requirements. Please contact your local Siemens Healthineers organization for further details. In the U.S., platelet aggregation testing is for research use only, not for use in diagnostic procedures.
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