A quantitative automated immunoassay for fibrinogen/fibrin degradation products

We describe a prototype quantitative automated assay for fibrin and fibrinogen degradation products, a particle-enhanced turbidimetric inhibition immunoassay (PETINIA) in the Du Pont aca discrete clinical analyzer. This assay involves a latex particle reagent with covalently bound fibrinogen and a polyclonal antiserum raised in rabbits against human fibrinogen. A special secondary sample-collection tube quantitatively removes fibrinogen from citrated plasma and inhibits further fibrinolysis, independent of heparin concentration. The assay range is 0-100 mg/L, in fibrinogen equivalents. The CV for the assay is less than 10% when performed with the aca. Nonclottable fibrin and fibrinogen fragments are measured by the assay, the greatest sensitivity being directed at the E domain of the fibrinogen molecule. We illustrate with case studies the potential of this assay for providing clinical information not obtainable with currently available qualitative and semi-quantitative assays.