title: A multi-center ring trial of allergen analysis using fluorescent multiplex array technology.
abstract: BACKGROUND
  Consistent performance of allergen assays is essential to ensure reproducibility of exposure assessments for investigations of asthma and occupational allergic disease. This study evaluated intra- and inter-laboratory reproducibility of a fluorescent multiplex array, which simultaneously measures eight indoor allergens in a single reaction well.
  
  
  METHODS
  A multi-center study was performed in nine laboratories in the US and Europe to determine the inter-laboratory variability of an 8-plex array for dust mite, cat, dog, rat, mouse and cockroach allergens. Aliquots of 151 dust extract samples were sent to participating centers and analyzed by each laboratory on three separate occasions. Agreement within and between laboratories was calculated by the concordance correlation coefficient (CCC).
  
  
  RESULTS
  Results were obtained for over 32,000 individual allergen measurements. Levels covered a wide range for all allergens from below the lower limit of detection (LLOD = 0.1-9.8 ng/ml) to higher than 6800 ng/ml for all allergens except Mus m 1, which was up to 1700 ng/ml. Results were reproducible within as well as between laboratories. Within laboratories, 94% of CCC were ≥ 0.90, and 80% of intra-laboratory results fell within a 10% coefficient of variance (CV%). Results between laboratories also showed highly significant positive correlations for all allergens (~0.95, p<0.001). Overall means of results were comparable, and inter-laboratory CV% for all allergens except Rat n 1 ranged between 17.6% and 26.6%.
  
  
  CONCLUSIONS
  The data indicate that performance criteria for fluorescent multiplex array technology are reproducible within and between laboratories. Multiplex technology provides standardized and consistent allergen measurements that will streamline environmental exposure assessments in allergic disease.
authors.affiliation: INDOOR Biotechnologies Inc, Charlottesville, VA 22903, USA. eking@inbio.com
authors.forename: Eva M
authors.initials: EM
authors.lastname: King
authors.forename: Stephanie
authors.initials: S
authors.lastname: Filep
authors.forename: Bryan
authors.initials: B
authors.lastname: Smith
authors.forename: Thomas
authors.initials: T
authors.lastname: Platts-Mills
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hamilton
authors.forename: Detlef
authors.initials: D
authors.lastname: Schmechel
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Sordillo
authors.forename: Donald
authors.initials: D
authors.lastname: Milton
authors.forename: Ronald
authors.initials: R
authors.lastname: van Ree
authors.forename: Esmeralda J M
authors.initials: EJ
authors.lastname: Krop
authors.forename: Dick J J
authors.initials: DJ
authors.lastname: Heederik
authors.forename: Nervana
authors.initials: N
authors.lastname: Metwali
authors.forename: Peter S
authors.initials: PS
authors.lastname: Thorne
authors.forename: Darryl C
authors.initials: DC
authors.lastname: Zeldin
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Sever
authors.forename: Agustin
authors.initials: A
authors.lastname: Calatroni
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Arbes
authors.forename: Herman E
authors.initials: HE
authors.lastname: Mitchell
authors.forename: Martin D
authors.initials: MD
authors.lastname: Chapman
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D000485:Allergens / Q000032:analysis*; D000818:Animals; D001249:Asthma / Q000175:diagnosis; D002415:Cats; D003058:Cockroaches; D004285:Dogs; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005060:Europe; D005453:Fluorescence; D006967:Hypersensitivity / Q000175:diagnosis; D007753:Laboratories / Q000592:standards*; D051379:Mice; D046228:Microarray Analysis / Q000379:methods*; D008925:Mites; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States
chemical_list: D000485:Allergens