title: Why human color vision cannot reliably detect cerebrospinal fluid xanthochromia.
abstract: BACKGROUND
  Visual assessment of cerebrospinal fluid (CSF) for xanthochromia (yellow color) is practiced by the majority of laboratories worldwide as a means of diagnosing intracranical bleeds.
  
  
  METHODS
  Colorimetric and spectrophotometric analysis of CSF samples for recognizing the presence of bilirubin either in low concentrations or in the presence of hemolysed blood.
  
  
  RESULTS
  The experiments provide the physiological and colorimetric basis for abandoning visual assessment of CSF for xanthochromia.
  
  
  CONCLUSIONS
  We strongly recommend relying on spectrophotometry as the analytical method of choice.
authors.affiliation: The National Hospital for Neurology and Neurosurgery, Department of Neuroimmunology, Institute of Neurology, Queen Square, London, UK. a.petzold@ion.ucl.ac.uk
authors.forename: Axel
authors.initials: A
authors.lastname: Petzold
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Keir
authors.forename: Ted L
authors.initials: TL
authors.lastname: Sharpe
mesh_terms: D001663:Bilirubin / Q000097:blood*; D002543:Cerebral Hemorrhage / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D002555:Cerebrospinal Fluid; D002624:Chemistry, Clinical / Q000379:methods*; D019411:Clinical Laboratory Techniques; D003118:Color Perception; D003124:Colorimetry / Q000379:methods*; D006801:Humans; D007755:Laboratories, Hospital; D010858:Pigmentation; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000379:methods*; D013345:Subarachnoid Hemorrhage / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D014796:Visual Perception
chemical_list: D001663:Bilirubin