title: Quantification of coagulation factor XIII activity by a thio-NADH based assay using factor XIII immuno-depleted plasma as a diluent for calibration.
abstract: BACKGROUND
  Accurate determination of factor XIII (FXIII) activity is crucial for replacement therapy. FXIII activity is typically determined using a coupled enzymatic reaction that measures nicotinamide adenine dinucleotide hydride (NADH) consumption at 340 nm.
  
  
  METHODS
  Here, we describe the development of a prototype for a novel FXIII activity assay for detection at 405 nm by replacing NADH with thio-NADH, and the application of FXIII immuno-depleted plasma as a diluent for calibration.
  
  
  RESULTS
  Performance data show up to two-fold lower susceptibility of the prototype assay to interferences from hemolyzed, icteric, and lipemic samples when compared to a NADH assay format. In addition, the use of FXIII immuno-depleted plasma as diluent for calibration improved recovery almost two-fold in the lower measurement range. The novel prototype assay correlates well with a conventional assay (r=0.98, y=0.99·x+2.17% FXIII, n=173).
  
  
  CONCLUSIONS
  The described prototype assay has the potential to (a) increase trueness of measurement of low levels of FXIII, (b) improve robustness due to reduction from interferences, and (c) can be used on a broad range of coagulation instruments due to its detection at 405 nm.
authors.affiliation: Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kappel
authors.forename: Sina
authors.initials: S
authors.lastname: Stephan
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Christ
authors.forename: Lena
authors.initials: L
authors.lastname: Pechmann
authors.forename: Christa
authors.initials: C
authors.lastname: Duwe
authors.forename: Bodo
authors.initials: B
authors.lastname: Fischer
authors.forename: Martin
authors.initials: M
authors.lastname: Hahn
authors.forename: Harald
authors.initials: H
authors.lastname: Althaus
authors.forename: Matthias
authors.initials: M
authors.lastname: Ehm
authors.forename: Herbert
authors.initials: H
authors.lastname: Schwarz
authors.forename: Frank
authors.initials: F
authors.lastname: Vitzthum
mesh_terms: D001780:Blood Coagulation Tests / Q000379:methods* / Q000592:standards; D002138:Calibration; D004796:Clinical Enzyme Tests / Q000379:methods* / Q000592:standards; D005176:Factor XIII / Q000032:analysis* / Q000378:metabolism; D005177:Factor XIII Deficiency / Q000175:diagnosis*; D006801:Humans; D009243:NAD / Q000378:metabolism
chemical_list: D009243:NAD; D005176:Factor XIII