title: Coagulation assays based on the Luminescent Oxygen Channeling Immunoassay technology 1).
abstract: BACKGROUND
  The Luminescent Oxygen Channeling Immunoassay (LOCI) technology is a well-established homogeneous assay format that allows for fast, accurate, and highly sensitive quantitation of analytes. We set out to develop and prove a novel concept to establish a LOCI format that should principally allow for the determination of the activity of coagulation factors and anticoagulants of clinical relevance.
  
  
  METHODS
  The concept is based on the linkage of LOCI nano-beads by a peptide that can be cleaved by a coagulation factor. To prove the principle, we used a peptide that can be cleaved by thrombin.
  
  
  RESULTS
  We were able to show that coagulation activation of plasma or whole blood samples that were combined with the LOCI components degraded the thrombin-sensitive peptide and consequently, led to a reduction of the LOCI signal. Signal reduction was proportional to the amount of active thrombin generated. The research prototype assay allowed for the detection of factor deficiencies in both the extrinsic and intrinsic coagulation pathways, and for the quantification of hirudin, a direct thrombin inhibitor.
  
  
  CONCLUSIONS
  Taken together, we conclude that the LOCI technology has the potential for extension to functional blood coagulation assays.
authors.affiliation: Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kappel
authors.forename: Sina
authors.initials: S
authors.lastname: Stephan
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Christ
authors.forename: Anja
authors.initials: A
authors.lastname: Haude-Barten
authors.forename: Madeleine
authors.initials: M
authors.lastname: Dahm
authors.forename: Herbert
authors.initials: H
authors.lastname: Schwarz
authors.forename: Bodo
authors.initials: B
authors.lastname: Fischer
authors.forename: Martin
authors.initials: M
authors.lastname: Hahn
authors.forename: Harald
authors.initials: H
authors.lastname: Althaus
authors.forename: Matthias
authors.initials: M
authors.lastname: Ehm
authors.forename: Frank
authors.initials: F
authors.lastname: Vitzthum
mesh_terms: D000991:Antithrombins / Q000097:blood / Q000494:pharmacology; D001780:Blood Coagulation Tests / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D026082:Singlet Oxygen / Q000737:chemistry*
chemical_list: D000991:Antithrombins; D026082:Singlet Oxygen