title: Evaluation of immunoassays for the measurement of erythropoietin (EPO) as an indirect biomarker of recombinant human EPO misuse in sport.
abstract: The measurement of serum erythropoietin (EPO) has been proposed as one of the indirect biomarkers for the detection of recombinant human EPO misuse in sport. An extended inter-laboratory validation of two commercial immunoassays for EPO measurement is described. A chemiluminescent immunoassay kit (CHEM) and an enzyme-linked immunosorbent assay kit (ELISA) were evaluated. The CHEM assay showed intra-laboratory precision better than 6% and correct accuracy values for all quality control samples tested. Precisions and accuracies better than 7 and 13%, respectively, were obtained for the ELISA assay for most of the quality control samples. The limit of quantification estimated for CHEM assay was lower than for the ELISA assay. Inter-laboratory concordance was good for both the assays, with lower dispersion shown by the CHEM assay. Results obtained with the ELISA assay were always lower than those of the CHEM assay. However, a good inter-technique correlation was obtained ([ELISA]=0.76 [CHEM]+0.06, r2=0.92). Quality control samples had a good stability after one and two freeze/thaw cycles and in simulated transportation conditions. In conclusion, CHEM and ELISA assays showed similar characteristics regarding intra-laboratory validation. Better inter-laboratory results were obtained with the CHEM assay and, hence, it is considered the recommended assay for anti-doping control analysis.
authors.affiliation: Unitat de Recerca en Farmacologia, Institut Municipal d'Investigació Mèdica, C/Doctor Aiguader 80, 08003 Barcelona, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Abellan
authors.forename: Rosa
authors.initials: R
authors.lastname: Ventura
authors.forename: Simona
authors.initials: S
authors.lastname: Pichini
authors.forename: Angel Francisco
authors.initials: AF
authors.lastname: Remacha
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Pascual
authors.forename: Roberta
authors.initials: R
authors.lastname: Pacifici
authors.forename: Rita
authors.initials: R
authors.lastname: Di Giovannandrea
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Zuccaro
authors.forename: Jordi
authors.initials: J
authors.lastname: Segura
mesh_terms: D000328:Adult; D004300:Doping in Sports / Q000517:prevention & control*; D004355:Drug Stability; D004356:Drug Storage; D004797:Enzyme-Linked Immunosorbent Assay; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D005615:Freezing; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D011994:Recombinant Proteins / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011933:Reagent Kits, Diagnostic; D011994:Recombinant Proteins; D004921:Erythropoietin