Quantification of coagulation factor XIII activity by a thio-NADH based assay using factor XIII immuno-depleted plasma as a diluent for calibration.
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.
Kappel
Andreas
A
Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany.
Stephan
Sina
S
Christ
Gerlinde
G
Pechmann
Lena
L
Duwe
Christa
C
Fischer
Bodo
B
Hahn
Martin
M
Althaus
Harald
H
Ehm
Matthias
M
Schwarz
Herbert
H
Vitzthum
Frank
F
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
D009243:NAD; D005176:Factor XIII