Validation, calibration, and specificity of quantitative D-dimer assays.
Assays for D-dimer antigen are based on monoclonal antibodies reactive with epitopes found on fibrin fragment D-dimer but not on fibrinogen fragment D, other fibrinogen degradation products, or native fibrinogen. The antibodies react with conformational epitopes generated by factor XIII-induced linkage of the C-terminal appendages of the fibrin gamma-chains of adjacent D-domains within a fibrin polymer. For some monoclonal antibodies, degradation of the cross-linked fibrin compound by plasmin is an additional requirement for the generation of the epitope. In clinical plasma samples, D-dimer antigen assays detect an array of fibrin compounds of different molecular weights, including fibrin fragment D-dimer as well as higher-molecular-weight fibrin degradation products and fibrin X-oligomers. Most D-dimer antigen represents cross-linked soluble fibrin present in circulation rather than degradation products from particulate clots. Due to differences in epitope reactivity, harmonization of D-dimer antigen assays can only be achieved with standard preparations containing a similar variety of cross-linked fibrin compounds. Assay technologies include manual latex agglutination assays, automated latex-enhanced light-scattering immunoassays, enzyme-linked immunoassays, and others.
Dempfle
Carl-Erik
CE
I Department of Medicine, University Hospital of Mannheim, Mannheim, Germany.
D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D015415:Biomarkers / Q000097:blood; D002138:Calibration; D005337:Fibrin / Q000096:biosynthesis; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; D005337:Fibrin