title: Optical Estimation of Beta 2 Microglobulin  during Hemodiafiltration – Does It Work?
abstract: BACKGROUND
  Currently, urea reduction seems to be the most widely used dialysis dose parameter. The aim of this study was to investigate the possibility to monitor beta 2-microglobulin (β2-M) elimination by utilizing the ultraviolet (UV) absorbance of spent dialysate.
  
  
  METHODS
  Blood and spent dialysate were collected during two week's sessions in 8 patients, one week in hemodialysis (HD) and one in hemodiafiltration (HDF). Correlation analysis between UV-wavelengths and concentrations of solutes in spent dialysate was performed. The reduction ratio (RR) of concentrations in blood, dialysate and UV-absorbance were compared.
  
  
  RESULTS
  Differences between HD and HDF were discovered in wavelength correlation maxima for the solutes. Relative error in RR (%) was larger (p < 0.05) for β2-M than for the other solutes. The most reasonable explanation is that β2-M does not absorb UV-radiation; instead, the absorbance of surrogate substances is measured.
  
  
  CONCLUSIONS
  A high correlation between UV-absorbance and β2-M can be achieved for HDF but not for HD. Still, UV-absorbance could perhaps be used in solely HDF mode for estimation of β2-M removal.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Uhlin
authors.forename: Jana
authors.initials: J
authors.lastname: Holmar
authors.forename: Pia
authors.initials: P
authors.lastname: Yngman-Uhlin
authors.forename: Anders
authors.initials: A
authors.lastname: Fernström
authors.forename: Ivo
authors.initials: I
authors.lastname: Fridolin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood; D015314:Dialysis Solutions / Q000737:chemistry*; D005260:Female; D017583:Hemodiafiltration; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy*; D007688:Kidneys, Artificial; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014508:Urea / Q000097:blood; D014527:Uric Acid / Q000097:blood; D001613:beta 2-Microglobulin / Q000097:blood*
chemical_list: D015314:Dialysis Solutions; D008567:Membranes, Artificial; D001613:beta 2-Microglobulin; D014527:Uric Acid; D014508:Urea; D003404:Creatinine