Determination of lipase catalytic activity in two reference materials: BCR 693 and BCR 694 by titrimetry at constant pH.
Because routine assays for pancreatic lipase catalytic activity are not yet standardized, between-method comparability is very poor. This is mainly due to the lack of reference materials (RMs). The aim of this study was to assign values of catalytic concentration to two human pancreatic lipase RMs, one prepared from human pancreatic juice (BCR 693), the other obtained by recombinant technology (BCR 694). Lipase catalytic activity was assayed in five experienced laboratories, using aliquots from the same lot of triolein emulsion and a standardized titrimetric procedure, optimized with regard to substrate, cofactors and pH. The accepted sets of data (n = 4) gave a mean +/- the corresponding uncertainty expressed as the 0.95 confidence interval of 1732 +/- 72 U/l and 1043 +/- 60 U/l for BCR 693 and 694, respectively. Transferability of the whole operating procedure proved to be quite satisfactory. The authors conclude that both RMs can be used to verify the correct implementation of the standardized measurement procedure and to assign values to secondary lipase materials (commercial calibrators, control products) which, in turn, ensures traceability to the standardized procedure in this study, and contributes to the harmonization of laboratory results according to the Directive for in vitro Diagnostic Medical Devices.
Lessinger
Jean-Marc
JM
Laboratoire de Biochimie appliquée, Faculté de Pharmacie, Université Louis Pasteur, Illkirch, France. jm.lessinger@evc.net
Parashou
Stella
S
Arzoglou
Panteleimon
P
Ramos
Paul
P
Chapus
Catherine
C
Dufaux
Jeanine
J
Junge
Wolfgang
W
Profilis
Christos
C
Férard
Georges
G
D000818:Animals; D002384:Catalysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D010179:Pancreas / Q000201:enzymology; D013552:Swine; D017186:Titrimetry; D014304:Triolein
D014304:Triolein; C480663:BCR 693; C480664:BCR 694; D008049:Lipase