Description:

RoxFactorXIaisachromogenicassaykitbaseduponFXagenerationforquantitativeactivitydeterminationofFactorXIainenrichedorhighlypurifiedproteinpreparations.Notintendedforanalysisofplasma.

• DetectionLimit=about0.03mU/mL
• Nouseofhumanplasma

MeasurementPrinciple:

HumanFXIaisdeterminedfromitsactivationofhumanFactorIXandensuingactivationofhumanFactorX.GeneratedFactorXaisthenmeasuredwithachromogenicFXasubstrate.

TheactivationofFactorIXisperformedintwosteps:

1. InitialactivationofFIXintheabsenceofphospholipids.
2. ContinuedactivationofFIXinthepresenceofFXandphospholipids,therewithallowingconcomitantactivationofFX.

Typicaldose-responsecurves:

Background:

FactorXI(FXI)hasbeenidentifiedasariskfactorforbotharterialandvenousthromboembolism(Ref1-3).PlasmafractionationproceduresmaysometimesbeassociatedwithinadvertentactivationofhemostasiszymogenproteinssuchasFXIandFactorXIa(FXIa)canbeacontaminantinintermediateorfinalproductssuchasimmunoglobulins(IgG).ThromboemboliceventshavebeenreportedtooccurafterintravenousadmiNISTrationofIgGandensuingdetailedanalysesappearedtolinktheseeventstothepresenceofFXIaintheadministeredIgGbatches(4-7).RoutinetestssuchastheNAPTTmaynotbesufficientlysensitivetodetectrelevantlowlevelsofFXIa,possIBLypartlyexplainedbymatrixinterference.RoxFactorXIaoffersahighlysensitivechromogenicmethodfordeterminationofsub-picomolarlevelsofFXIa,therewithallowinghighsampledilutionsandminimizinginterferencefromthesamplematrixandfromcontaminatingproteinssuchaskallikrein,zymogenFXIandFIXa.

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