title: Multisite evaluation of a monoclonal IMMULITE erythropoietin immunoassay.
abstract: BACKGROUND
  Erythropoietin (EPO) measurements are useful in diagnosing anemias and polycythemias. We conducted a multisite evaluation of a monoclonal IMMULITE® EPO immunoassay.(1) DESIGN AND METHODS: The IMMULITE EPO assay is a solid-phase enzyme-labeled chemiluminescent immunometric assay. Method comparison to the Beckman ACCESS 2 assay using clinically characterized samples and reproducibility studies were conducted at three external independent laboratories. Internal evaluation conducted at Siemens included comparison of IMMULITE® 2000 and IMMULITE® 1000 assays to the ACCESS 2 assay; imprecision; linearity; limit of blank (LoB), limit of detection (LoD), and functional sensitivity; potential interference and cross-reactants; and reference interval determination.
  
  
  RESULTS
  External method comparison gave Deming regression of (IMMULITE 2000)=0.96(ACCESS 2)+2.57IU/L, r=0.98 (n=217). Reproducibility ranged from 6.1% to 16.2%. Internal method comparisons gave Deming regressions of (IMMULITE 2000)=1.09(ACCESS 2)-3.51IU/L, r=0.98 and (IMMULITE 1000)=0.95(ACCESS 2)+0.52IU/L, r=0.95. Total imprecision ranged from 6.4% to 10.3% and linearity was confirmed from 3.5 to 562IU/L. LoB, LoD, and functional sensitivity were 0.5, 1.0, and 1.5IU/L, respectively. The assay was highly specific for EPO. Nonparametric reference interval was 4.3 to 29.0IU/L (n=170).
  
  
  CONCLUSIONS
  The monoclonal IMMULITE EPO assay showed acceptable performance for EPO measurement.
authors.affiliation: ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Owen
authors.affiliation: Women and Infants Hospital of Rhode Island, Providence, RI, USA.
authors.forename: Geralyn
authors.initials: G
authors.lastname: Lambert-Messerlian
authors.affiliation: Quest Diagnostics, Valencia, CA, USA.
authors.forename: Cabrini
authors.initials: C
authors.lastname: Delaney
authors.affiliation: University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Christenson
authors.affiliation: Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Plouffe
authors.affiliation: Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA.
authors.forename: Rocio
authors.initials: R
authors.lastname: Ludewig
authors.affiliation: Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Woods
authors.affiliation: Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA.
authors.forename: Jyh-Dar
authors.initials: JD
authors.lastname: Lei
authors.affiliation: Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA.
authors.forename: Stephan
authors.initials: S
authors.lastname: Thompson
authors.affiliation: ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA; Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Roberts
authors.affiliation: ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA; Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT, USA. Electronic address: joely.a.straseski@aruplab.com.
authors.forename: Joely A
authors.initials: JA
authors.lastname: Straseski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D004921:Erythropoietin / Q000097:blood* / Q000276:immunology; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D011086:Polycythemia / Q000097:blood* / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D004921:Erythropoietin
keywords: Chemiluminescent immunoassay; IMMULITE; Imprecision; Interference; Method comparison; Reference interval; Serum erythropoietin