title: Comparing plasma, serum and whole blood indium concentrations from workers at an indium-tin oxide (ITO) production facility.
abstract: OBJECTIVE
  Occupational exposure to indium compounds including indium-tin oxide (ITO) can result in potentially fatal indium lung disease. We compared plasma, serum and whole blood indium concentrations (InP, InSand InB) from workers at a single ITO production facility to assess the comparability of these matrices used for biological monitoring of indium exposure.
  
  
  METHODS
  InP, InSand InBwere measured using inductively coupled mass spectrometry from consenting workers at an ITO production facility with specimen collection occurring during June-July 2014. Matched pairs from workers were assessed to determine the matrix relationships using the Pearson correlation, paired t-tests, per cent difference, linear regression and κ statistics.
  
  
  RESULTS
  Indium matrices were collected from 80 workers. Mean (SD) InP, InSand InBwere 3.48 (3.84), 3.90 (4.15) and 4.66 (5.32) mcg/L, respectively. The InS-InPdifference was 14%; InSwas higher in all but two workers. InPand InSwere highly correlated (r=>0.99). The InB-InSdifference was 19%; InBwas higher in 85% of workers. The InB-InPdifference was 34%; InBwas higher in 66% of workers. InBwas highly correlated with both InPand InS(r=0.97 and 0.96, respectively). κ Statistics were 0.84, 0.83 and 0.82 for InP, InSand InB, respectively, for individuals with each matrix ≥1 mcg/L (p<0.01).
  
  
  CONCLUSIONS
  While all matrices were highly correlated, we encourage the use of InPand InSto reliably compare studies across different populations using different matrices. The higher per cent difference and increased variability of InBmay limit its utility in comparisons with InPand InSin different populations.
authors.affiliation: National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, USA.
authors.forename: R Reid
authors.initials: RR
authors.lastname: Harvey
authors.affiliation: National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, USA.
authors.forename: M Abbas
authors.initials: MA
authors.lastname: Virji
authors.affiliation: National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, USA.
authors.forename: Nicole T
authors.initials: NT
authors.lastname: Edwards
authors.affiliation: National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, USA.
authors.forename: Kristin J
authors.initials: KJ
authors.lastname: Cummings
mesh_terms: D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D007204:Indium / Q000097:blood*; D000072499:Manufacturing and Industrial Facilities; D009314:National Institute for Occupational Safety and Health, U.S.; D016273:Occupational Exposure / Q000032:analysis*; D010949:Plasma / Q000737:chemistry; D044967:Serum / Q000737:chemistry; D017971:Tin Compounds / Q000097:blood*; D014481:United States
chemical_list: D017971:Tin Compounds; D007204:Indium; C109984:indium tin oxide
keywords: Blood matrices; Indium lung disease; Indium-tin oxide (ITO)