title: An interlaboratory study of perfluorinated alkyl compound levels in human plasma.
abstract: We conducted an interlaboratory study which differed from the typical study of this type because of its emphasis on comparing intralaboratory variability in results. We sent specimens to six laboratories experienced in the analysis of perfluorinated alkyl compounds in blood matrices and that use stringent procedures to control and assure accuracy and precision. Each received an identical set of 60 plasma specimens that were analyzed in six completely independent batches. Split specimens were included so that within- and between-batch coefficients of variation could be calculated. All laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorohexanesulfonate (PFHxS) measured in the specimens in general showed a high level of agreement, although in some cases the agreement was only moderate. The average within- and between-batch coefficient of variation for PFOS was 9.1% and 9.3%; for PFOA was 14.5% and 14.5%; and for PFHxS was 14.5% and 17.0%. The recent availability of labeled internal standards, among other advances, has facilitated improvement in the accuracy and precision of the assays. Considering the degree of between-subject variation in levels among people in background-exposed populations, the results indicate that biomarker-based epidemiologic studies of associations with health could have reasonable precision.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, P.O. Box 12233, MD A3-05, Research Triangle Park, NC 27709, USA. longnec1@niehs.nih.gov
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Longnecker
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Smith
authors.forename: Grace E
authors.initials: GE
authors.lastname: Kissling
authors.forename: Jane A
authors.initials: JA
authors.lastname: Hoppin
authors.forename: John L
authors.initials: JL
authors.lastname: Butenhoff
authors.forename: Emily
authors.initials: E
authors.lastname: Decker
authors.forename: David J
authors.initials: DJ
authors.lastname: Ehresman
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ellefson
authors.forename: John
authors.initials: J
authors.lastname: Flaherty
authors.forename: Michael S
authors.initials: MS
authors.lastname: Gardner
authors.forename: Eric
authors.initials: E
authors.lastname: Langlois
authors.forename: Alain
authors.initials: A
authors.lastname: Leblanc
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Lindstrom
authors.forename: William K
authors.initials: WK
authors.lastname: Reagen
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Strynar
authors.forename: William B
authors.initials: WB
authors.lastname: Studabaker
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D004784:Environmental Monitoring / Q000592:standards*; D004785:Environmental Pollutants / Q000032:analysis*; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D008297:Male; D011247:Pregnancy
chemical_list: D015415:Biomarkers; D004785:Environmental Pollutants; D005466:Fluorocarbons