Test Catalog

Test ID: PSF    
Protein S Antigen, Free, Plasma

Method Description Describes how the test is performed and provides a method-specific reference

This assay is performed using the HemosIL Free Protein S kit on the Instrumentation Laboratory ACL TOP. The assay uses latex immunoassay methodology to determine the presence of free protein S. It consists of 2 latex reagents, one being latex particles coated with purified human C4BP and the other is latex particles coated with a monoclonal antibody directed against human protein S. Patient plasma is combined with the purified C4BP that reacts with a high affinity for free protein S in the patient plasma. The free protein S adsorbed on the C4BP latex triggers the agglutination reaction with the second latex reagent. The aggregates form diameters greater than the wavelength of the light (405 nm) passing through, causing absorption of the light. This change in absorption is measured over time and reported as delta optical density (OD). The increase in absorption is proportional to the concentration of free protein S antigen present in the patient plasma.(Package insert: HemosIL Free Protein S. Instrumentation Laboratory Company, Lexington, MA, R06, 04/2004)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 4 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location Indicates the location of the laboratory that performs the test