title: Ultraviolet and visible light spectrophotometric approach to blood typing: objective analysis by agglutination index.
abstract: BACKGROUND
  A new blood typing technology based on ultraviolet (UV) and visible light spectroscopy (UV/visible spectroscopy) has been developed. Blood groups and types are determined by quantifying reproducible changes in the UV and visible light spectra of blood in the presence of agglutinating antibodies.
  
  
  METHODS
  Samples of red cells in the presence and absence of agglutinating antibodies were examined by UV/visible spectroscopy. Blood groups and types were determined by comparing the optical density spectra obtained between 665 and 1000 nm. These comparisons generate numbers (agglutination index) ranging from 0 to 100, with smaller numbers corresponding to lack of agglutination and larger numbers corresponding to agglutination.
  
  
  RESULTS
  The optical density of agglutinated blood is dramatically different from that of unagglutinated blood. The agglutination index derived from the relative slopes of the spectra is an objective indicator of agglutination strength. An agglutination index greater than 17 consistently and accurately established blood group- and type-specific agglutination.
  
  
  CONCLUSIONS
  The method accurately predicted A, B, and O blood groups, and D type in over 275 samples. Scattering theory-based calculations of relative volumes of red cells before and after agglutination show a direct correlation with the agglutination index and provide the theoretical basis of the analysis. This quantitative technique is reproducible and has the potential for automation.
authors.affiliation: Department of Chemistry, University of South Florida, and Florida Blood Services, Tampa 33620, USA.
authors.forename: S
authors.initials: S
authors.lastname: Narayanan
authors.forename: S
authors.initials: S
authors.lastname: Orton
authors.forename: G F
authors.initials: GF
authors.lastname: Leparc
authors.forename: L H
authors.initials: LH
authors.lastname: Garcia-Rubio
authors.forename: R L
authors.initials: RL
authors.lastname: Potter
mesh_terms: D001788:Blood Grouping and Crossmatching / Q000379:methods*; D006384:Hemagglutination; D006386:Hemagglutination Tests; D006801:Humans; D008954:Models, Biological; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013053:Spectrophotometry; D014466:Ultraviolet Rays