Record Display for the EPA National Library Catalog


Main Title Interlaboratory Study of Cellular Fluorescence Intensity Measurements with Fluorescein-Labeled Microbead Standards.
Author Vogt, R. F. ; Cross, G. D. ; Phillips, D. L. ; Henderson, L. O. ; Hannon., W. H. ;
CORP Author NSI Technology Services Corp., Corvallis, OR. Environmental Research Lab. ;Centers for Disease Control, Atlanta, GA.
Publisher c1991
Year Published 1991
Report Number EPA/600/J-92/096;
Stock Number PB92-153899
Additional Subjects Interlaboratory comparisons ; Environmental monitoring ; Data processing ; Research and development ; Sampling ; Case studies ; Quality assurance ; Error analysis ; Quality control ; Statistical analysis ; Water pollution sampling ; Reprints ; Watershed Manipulation Project
Library Call Number Additional Info Location Last
NTIS  PB92-153899 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 13p
Assessing and achieving interlaboratory comparability is a major quality assurance challenge for large interdisciplinary, multi-institutional, environmental research projects. Eight laboratories routinely measure chemical constituents of various field and laboratory derived solution samples as part of the US EPA's Watershed Manipulation Project. A quarterly interlaboratory comparison study has been designed by EPA quality assurance personnel in Corvallis, OR (USA) to assess: (1) intralaboratory precision and accuracy, (2) interlaboratory precision, and (3) trends through time. Synthetic solution samples are prepared quarterly and sent via overnight express to participating laboratories. For each analyte, laboratories are requested to perform analyses in triplicate with each replicate measured under different calibrations; precision calculated from resulting data therefore includes a component of among-batch variability. Relative bias is calculated as the percent difference between a laboratory's mean and the median of the laboratories (the supplying laboratory's value being treated equally to the other laboratories). Overall precision is expressed as the coefficient of variation using laboratory means. An ANOVA approach is also used to calculate significant differences among laboratories. Data interpretation and results from four quarterly evaluations will be presented.