title: Evaluation of two fully automated novel enzyme-linked immunosorbent assays for the determination of human adiponectin in serum.
abstract: BACKGROUND
  In contrast to RIA, recently available ELISAs provide the potential for fully automated analysis of adiponectin. To date, studies reporting on the diagnostic characteristics of ELISAs and investigating on the relationship between ELISA- and RIA-based methods are rare.
  
  
  METHODS
  Thus, we established and evaluated a fully automated platform (BEP 2000; Dade-Behring, Switzerland) for determination of adiponectin levels in serum by two different ELISA methods (competitive human adiponectin ELISA; high sensitivity human adiponectin sandwich ELISA; both Biovendor, Czech Republic). Further, as a reference method, we also employed a human adiponectin RIA (Linco Research, USA). Samples from 150 patients routinely presenting to our cardiology unit were tested.
  
  
  RESULTS
  ELISA measurements could be accomplished in less than 3 h, measurement of RIA had a duration of 24 h. The ELISAs were evaluated for precision, analytical sensitivity and specificity, linearity on dilution and spiking recovery. In the investigated patients, type 2 diabetes, higher age and male gender were significantly associated with lower serum adiponectin concentrations. Correlations between the ELISA methods and the RIA were strong (competitive ELISA, r=0.82; sandwich ELISA, r=0.92; both p<0.001). However, Deming regression and Bland-Altman analysis indicated lack of agreement of the 3 methods preventing direct comparison of results. The equations of the regression lines are: Competitive ELISA=1.48 x RIA-0.88; High sensitivity sandwich ELISA=0.77 x RIA+1.01.
  
  
  CONCLUSIONS
  Fully automated measurement of adiponectin by ELISA is feasible and substantially more rapid than RIA. The investigated ELISA test systems seem to exhibit analytical characteristics allowing for clinical application. In addition, there is a strong correlation between the ELISA methods and RIA. These findings might promote a more widespread use of adiponectin measurements in clinical research.
authors.affiliation: Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Carinagasse 47, 6800 Feldkirch, Austria. lorenzrisch@hotmail.com
authors.forename: Lorenz
authors.initials: L
authors.lastname: Risch
authors.forename: Guenter
authors.initials: G
authors.lastname: Hoefle
authors.forename: Christoph
authors.initials: C
authors.lastname: Saely
authors.forename: Sabine
authors.initials: S
authors.lastname: Berchthold
authors.forename: Martina
authors.initials: M
authors.lastname: Weber
authors.forename: Ghazaleh
authors.initials: G
authors.lastname: Gouya
authors.forename: Philipp
authors.initials: P
authors.lastname: Rein
authors.forename: Peter
authors.initials: P
authors.lastname: Langer
authors.forename: Thomas
authors.initials: T
authors.lastname: Marte
authors.forename: Stefan
authors.initials: S
authors.lastname: Aczel
authors.forename: Heinz
authors.initials: H
authors.lastname: Drexel
mesh_terms: D052242:Adiponectin / Q000097:blood; D000367:Age Factors; D000368:Aged; D001322:Autoanalysis / Q000295:instrumentation / Q000379:methods; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D011863:Radioimmunoassay / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin