title: ELISA for determination of total coagulation factor XII concentration in human plasma.
abstract: Human blood coagulation factor XII (FXII) is the one chain 80 kDa zymogen form of the active serine protease α-FXIIa, which consists of a heavy and light chain linked by a disulfide bond, the light chain being responsible for the proteolytical activity. FXII is the first component of the contact dependent pathway of coagulation, but its physiological role is still subject to debate. In the present study we utilized two monoclonal antibodies against the heavy chain of FXII to establish a sandwich enzyme linked immunosorbent assay (ELISA) for quantification of total FXII concentration in human plasma samples. A unique characteristic of this assay is its equal recognition of FXII and inhibitor bound FXII. This is important, as inhibitor complexes of α-FXIIa are formed in vivo as well as during blood sampling and handling. Validation of the assay demonstrated a high sensitivity, with a limit of detection and quantification of 1.2 ng/mL and 2.6 ng/mL respectively. The coefficients of variation for the repeatability and within-laboratory standard deviations were 2.6% and 5.2% respectively. The reference interval determined from healthy volunteers (n=240) was 10.6-43 mg/L.
authors: University of Southern Denmark, Institute of Public Health, Unit for Thrombosis Research, Campus Esbjerg, Niels Bohrs Vej 9-10, 6700 Esbjerg, Denmark. dmadsen@health.sdu.dk
authors: Daniel Elenius
authors: DE
authors: Madsen
authors: Johannes Jakobsen
authors: JJ
authors: Sidelmann
authors: Kathrine
authors: K
authors: Overgaard
authors: Claus
authors: C
authors: Koch
authors: Jørgen Brodersen
authors: JB
authors: Gram
mesh_terms: D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005174:Factor XII / Q000032:analysis*; D006801:Humans; D057230:Limit of Detection
chemical_list: D005174:Factor XII
keywords: 4-PL; 4-parameter nonlinear logistic curve fitting; ANCOVA; APlC; B; C1-inh; C1-inhibitor; CV; Coagulation factor XII; ELISA; FPLC; FXII; Fibrinolysis; HRP; IV; LOD; LOQ; MAb; O/N; OD; PBS; PK; RD; RT; S(r); SD; Strp; TW; Thrombosis; Validation; analysis of covariance; anti phospholipid syndrome; coagulation factor XII; coefficient of variation; complement C1 esterase inhibitor; enzyme linked immunosorbent assay; estimate of repeatability standard deviation; fast protein liquid chromatography; horseradish peroxidase; intravenously; kDa; kilo Dalton; limit of detection; limit of quantitation; monoclonal antibody; optical density; over night; phosphate buffered saline; plasma kallikrein; relative dilution; room temperature; standard deviation; streptavidin; tween; within-laboratory standard deviation