Search tips
Search criteria 


Logo of bmcmrmBioMed Centralsearchsubmit a manuscriptregisterthis articleBMC Medical Research Methodology
BMC Med Res Methodol. 2012; 12: 40.
Published online Mar 31, 2012. doi:  10.1186/1471-2288-12-40
PMCID: PMC3340310
Determination of inflammatory biomarkers in patients with COPD: a comparison of different assays
José L López-Campos,corresponding author1,2 Elena Arellano,2 Carmen Calero,1,2 Ana Delgado,3 Eduardo Márquez,1 Pilar Cejudo,1 Francisco Ortega,1,2 Francisco Rodríguez-Panadero,1,2 and Ana Montes-Worboys1,2
1Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, Sevilla, Spain
2CIBER de Enfermedades Respiratorias (CIBERES), Sevilla, Spain
3Departamento de Bioquímica, Hospital Universitario Virgen del Rocío, Sevilla, Spain
corresponding authorCorresponding author.
José L López-Campos: lcampos/at/; Elena Arellano: elena_arellano8/at/; Carmen Calero: carmencalero/at/; Ana Delgado: anal.delgado.sspa/at/; Eduardo Márquez: eduardo.marquez.sspa/at/; Pilar Cejudo: mariap.cejudo.sspa/at/; Francisco Ortega: francisco.ortega.sspa/at/; Francisco Rodríguez-Panadero: frodriguezpan/at/; Ana Montes-Worboys: amontes-ibis/at/
Received August 23, 2011; Accepted March 31, 2012.
Chronic obstructive pulmonary disease (COPD) is an inflammatory pulmonary disorder with systemic inflammatory manifestations that are mediated by circulating acute-phase reactants. This study compared an enzyme-linked immunosorbent assay (ELISA) to a nephelometric technique for the measurement of serum C-reactive protein (CRP) and serum amyloid A (SAA) and investigated how the choice of assay influenced the estimation of inflammation in patients with stable COPD.
CRP and SAA concentrations measured by ELISA and nephelometry in 88 patients with COPD and 45 control subjects were used to evaluate the performance of these methods in a clinical setting.
With both assays, the concentrations of CRP and SAA were higher in COPD patients than in controls after adjustment for age and sex. There was a moderate correlation between the values measured by ELISA and those measured by nephelometry (logCRP: r = 0.55, p < 0.001; logSAA: r = 0.40, p < 0.001). However, the concentrations of biomarkers determined by nephelometry were significantly higher than those obtained with ELISA for CRP (mean difference = 2.7 (9.4) mg/L) and SAA (mean difference = 0.31 (14.3) mg/L).
Although the serum CRP and SAA concentrations measured by ELISA and nephelometry correlated well in COPD patients, the ELISA values tended to be lower for CRP and SAA when compared with nephelometric measurements. International standardization of commercial kits is required before the predictive validity of inflammatory markers for patients with COPD can be effectively assessed in clinical practice.
Articles from BMC Medical Research Methodology are provided here courtesy of
BioMed Central