cTn was measured in 575 sample pairs on the Abbott Architect cTnI, Beckman Coulter Access2 cTnI, Roche Cobas cTnT and Siemens ADVIA Centaur cTnI methods.
Good agreement was obtained amongst all methods with a universal z-value cut-off (¦Ê>0.79) and method specific fixed ¦¤ cut-offs (¦Ê>0.82) while suboptimal agreement was obtained between cTnI and cTnT with fixed % ¦¤ cut-offs (¦Ê < 0.50).
Fixed ¦¤ cut-offs will perform well at low cTn concentrations while fixed % ¦¤ cut-off values are predicted to perform poorly. z-Values are independent of the cTn concentration, present differences as a continuum of probability and a universal decision level can be used for all cTnI and cTnT methods.