Analytical considerations for free protein S assays in protein S deficiency
Protein S is an anticoagulant protein that circulates in plasma in complex with C4b-binding protein; (C4BP) or in free form. Deficiency of protein S increases the risk of venous thrombosis. Measurement of free protein S, as compared to total levels, has been shown to be superior for prediction of protein S deficiency. We studied the effects of different handling protocols for an immuno- and a liga