title: Investigation of saliva as an alternative matrix to blood for the biological monitoring of inorganic lead.
abstract: BACKGROUND
  Whole blood is the established matrix for biological monitoring of inorganic lead; however blood sampling is an invasive procedure. Saliva offers a potential non-invasive alternative. This study determines lead in whole blood and saliva. A novel method for saliva sampling and preparation is presented.
  
  
  METHODS
  Paired blood and saliva samples were obtained from 105 occupationally exposed UK workers. Saliva was collected using a StatSure sampling device, and a nitric acid digestion step was incorporated. The utility of the device for this application was evaluated. Whole blood was obtained by venepuncture. Analyses were carried out by ICP-MS.
  
  
  RESULTS
  The limit of detection for lead in saliva was 0.011 μg/L. Mean blank-corrected recovery from 10 μg/L spiked saliva was 65.9%. The mean result from blank saliva extracted through the StatSure device was 2.86 μg/L, compared to 0.38 μg/L by direct analysis. For the paired samples, median blood lead was 6.00 μg/dL and median saliva lead was 17.1 μg/L. Pearson's correlation coefficient for saliva lead versus blood lead was 0.457 (95% C.I. 0.291-0.596).
  
  
  CONCLUSIONS
  ICP-MS analysis allows sensitive determination of lead in saliva with low limits of detection. The StatSure device is effective for high occupational exposures, but contamination from the device could confound lower-level measurements. Saliva would only be effective as a surrogate for whole blood for highly-exposed populations, although with further work it may have applications as a biomarker of recent exposure.
authors.affiliation: Health and Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK. Electronic address: james.staff@hsl.gsi.gov.uk.
authors.forename: James F
authors.initials: JF
authors.lastname: Staff
authors.affiliation: Health and Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK.
authors.forename: Anne-Helen
authors.initials: AH
authors.lastname: Harding
authors.affiliation: Health and Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK.
authors.forename: Jackie
authors.initials: J
authors.lastname: Morton
authors.affiliation: Health and Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: Jones
authors.affiliation: Coventry Diagnostics LLC, 1197 Rochester Road, Troy, MI 48083, USA.
authors.forename: Erica A
authors.initials: EA
authors.lastname: Guice
authors.affiliation: Coventry Diagnostics LLC, 1197 Rochester Road, Troy, MI 48083, USA.
authors.forename: Thom
authors.initials: T
authors.lastname: McCormick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007854:Lead / Q000097:blood* / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D012463:Saliva / Q000737:chemistry*; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D007854:Lead
keywords: Biological monitoring; Blood; ICP-MS; Lead; Occupational exposure; Saliva