Overestimation of N-glycoPEGylated factor IX activity in a one-stage factor IX clotting assay owing to silica-mediated premature conversion to activated factor IX

摘要

Background Clinical laboratories routinely quantify factor IX (FIX) activity by measurement of the activated partial thromboplastin time (APTT) in a one-stage (OS) clotting assay. This assay can be performed with any of a plethora of differently composed APTT reagents, giving variable recovery when applied to nonacog beta pegol (N9-GP), an N-glycoPEGylated recombinant FIX.