title: Variance in multiplex suspension array assays: microsphere size variation impact.
abstract: BACKGROUND
  Luminex suspension microarray assays are in widespread use. There are issues of variability of assay readings using this technology.
  
  
  RESULTS
  Size variation is demonstrated by transmission electron microscopy. Size variations of microspheres are shown to occur in stepwise increments. A strong correspondence between microsphere size distribution and distribution of fluorescent events from assays is shown. An estimate is made of contribution of microsphere size variation to assay variance.
  
  
  CONCLUSIONS
  A probable significant cause of variance in suspended microsphere assay results is variation in microsphere diameter. This can potentially be addressed by changes in the manufacturing process. Provision to users of mean size, median size, skew, the number of standard deviations that half the size range represents (sigma multiple), and standard deviation is recommended. Establishing a higher sigma multiple for microsphere production is likely to deliver a significant improvement in precision of raw instrument readings. Further research is recommended on the molecular architecture of microsphere coatings.
authors: Microbiology Graduate Group, University of California, Davis, CA 95616, USA. bphanley@ucdavis.edu
authors: Brian P
authors: BP
authors: Hanley
authors: Li
authors: L
authors: Xing
authors: R Holland
authors: RH
authors: Cheng
mesh_terms: D005453:Fluorescence; D046228:Microarray Analysis / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D015203:Reproducibility of Results
references: Cytometry A. 2006 May;69(5):384-90
references: 16615139
references: Cytometry A. 2006 May;69(5):374-83
references: 16604539