title: A direct, automated, immuno-turbidimetric assay of free protein S antigen in plasma.
abstract: A new, fully automated, one-step, immuno-turbidimetric assay of free protein S (fPS) in plasma (STA Liatest Free Protein S; Diagnostica Stago, Asnières, France) has been developed for STA analysers. This technique combines the advantages of a direct assay of fPS using two monoclonal antibodies, which specifically recognize fPS but not protein S (PS)-C4b-binding protein complexes, and the advantages of automation. The assay has good analytical performances, with intra- and inter-assay variation coefficients below 5% for normal values, and slightly higher for abnormal values. In a comparison study with a one-step enzyme-linked immunosorbent assay for fPS (Asserachrom Free Protein S; Diagnostica Stago), a correlation coefficient of 0.93 with a regression line close to 1 was found between the two techniques (n = 166 normal or PS-deficient plasma samples collected from healthy subjects and individuals with a personal or family history of thrombosis). This new technique is specific, reproducible, easy to perform, and provides a useful tool in the diagnosis of PS deficiency.
authors: Unité d'Hémostase et de Thrombose, Centre Hospitalier et Universitaire Henri Mondor, Université Paris Val de Marne et AP-HP, Créteil, France.
authors: C
authors: C
authors: Deffert
authors: F
authors: F
authors: Esteve
authors: M
authors: M
authors: Grimaux
authors: M
authors: M
authors: Gouault-Heilmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D001322:Autoanalysis; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D017293:Protein S / Q000032:analysis*; D018455:Protein S Deficiency / Q000097:blood / Q000175:diagnosis*; D011786:Quality Control; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012727:Sex Characteristics
chemical_list: D000911:Antibodies, Monoclonal; D017293:Protein S