title: Intra- and inter-laboratory reproducibility of estrogen and progesterone receptor enzyme immunoassay in breast cancer cytosol samples--a Swedish multicenter study. Swedish Society of Cancer Study Group.
abstract: Estrogen and progesterone receptor analysis results were compared within and between six laboratories in Sweden using frozen breast cancer cytosol samples, and the same technique (enzyme immunoassay, Abbott Laboratories). The concordance in receptor status (positive vs. negative) was excellent (98.4% (571/580)). The discordant results were attributable to values near cut-off (n = 4) or outliers (n = 5), the latter probably being due to analytical errors. One laboratory reported significantly higher ER concentrations than the others; thus caution should be observed when comparing absolute values from different centers. For PgR there were similar differences between the laboratories. However, the intra- and inter-laboratory differences were small compared with the overall variability in ER and PgR content between different samples in a large database. The range of the median intra-laboratory coefficient of variation was 11-23% for ER and 12-19% for PgR, indicating that there is room for improvement in the quality of assay performance.
authors.affiliation: Jubileum Institute, Department of Oncology, University Hospital, Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Fernö
authors.forename: P O
authors.initials: PO
authors.lastname: Bendahl
authors.forename: A
authors.initials: A
authors.lastname: Brisfors
authors.forename: K
authors.initials: K
authors.lastname: Byman
authors.forename: M
authors.initials: M
authors.lastname: Ekeberg
authors.forename: L
authors.initials: L
authors.lastname: Ferraud
authors.forename: K
authors.initials: K
authors.lastname: Grankvist
authors.forename: B
authors.initials: B
authors.lastname: Hjalmers
authors.forename: A
authors.initials: A
authors.lastname: Nilsson
authors.forename: G
authors.initials: G
authors.lastname: Sellberg
authors.forename: L
authors.initials: L
authors.lastname: Skoog
authors.forename: O
authors.initials: O
authors.lastname: Stål
authors.forename: I
authors.initials: I
authors.lastname: Wingmo
mesh_terms: D001943:Breast Neoplasms / Q000648:ultrastructure*; D003600:Cytosol / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D015588:Observer Variation; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D015203:Reproducibility of Results
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone