Free Protein S Antigen will be performed.
Do not order if the patient has received Coumadin for the past two weeks. If patient is on a stable dose of Coumadin (2 weeks), see Protein S Antigen, On Coumadin test (PROT-SM).
Free Protein S Antigen is the initial test in the algorithm for the diagnosis of Protein S deficiency. This assay has better accuracy and less potential interference that Protein S Activity.
When indicated, Protein S Activity testing will be initiated by a clinical pathologist who has reviewed the case.