%0 Journal Article %J Scand.J.Clin.Lab Invest %D 2007 %T Performance of automated measurement of antibodies to cyclic citrullinated peptide in the routine clinical laboratory97 %A C . Van Campenhout %A Van Cotthem,K.A. %A Stevens,W.J. %A De Clerck,L.S. %K 0 %K a %K ACCP %K Adult %K Aged %K Agreement %K an %K analysis %K antibodies %K Antibody %K Antwerp %K ARTHRITIS %K article %K AS %K Automation %K Belgium %K Case %K chemistry %K Clinical %K Control %K cutoff %K Diagnostics %K disease %K estimation %K Female %K Healthy %K hospital %K Humans %K im %K Immunoassay %K Immunoenzyme Techniques %K immunology %K improve %K Increase %K IS %K journal %K Laboratories %K Male %K Marker %K measurement %K method %K methods %K middle aged %K n %K Objective %K Patient %K patients %K Peptides %K Peptides,Cyclic %K performance %K Print %K protein %K Reproducibility %K Reproducibility of Results %K response %K result %K results %K Rheumatoid Factor %K Roc Curve %K routine %K SB - IM %K SENSITIVITY %K specificity %K standards %K study %K System %K Systems %K Technique %K Universities %K university %K university hospital %K variation %X OBJECTIVE: To evaluate the performing technical and clinical characteristics of an automated system for routine measurement of anticyclic citrullinated peptide antibodies (aCCP), a new marker for rheumatoid arthritis (RA). MATERIAL AND METHODS: Reproducibility, repeatability and linearity of aCCP, as measured by an automated fluorescent enzyme immunoassay (FEIA/Phadia), were evaluated and compared with the performance of a manual ELISA technique (Axis Shield Diagnostics). Clinical verification of both methods included estimation of sensitivity in RA patients (n = 42) and specificity in well-characterized non-RA autoimmune disease controls (n = 49) and healthy subjects (n = 39). RESULTS: Precision studies showed a coefficient of variation between 4.9 % and 10 % for the FEIA technique and between 6.35% and 19% for the ELISA technique. Both systems showed good linear response. Sensitivity of aCCP for RA was 74% for FEIA and 79% for ELISA. Specificity was 100% for both methods, as calculated for healthy subjects. For non-RA-diseased controls, specificities of 98% and 94% were obtained for FEIA and ELISA, respectively. Both methods were concordant in 97% of cases. Increasing the cut-off for the ELISA system from >5 U/mL to >11 U/mL resulted in lower sensitivity (71.4%) but higher specificity (98.0%), i.e. improved discriminating power between RA and non-RA and 100% agreement between both methods. CONCLUSION: Automated FEIA measurement of aCCP in the routine clinical laboratory improves imprecision compared to the manual ELISA. Our preliminary results suggest that an increase in cut-off for the ELISA can improve specificity to RA from 94% to 98 % %B Scand.J.Clin.Lab Invest %V 67 %P 859 - 867 %8 0/0/2007 %G eng %N 8 %1 39007 %& 859 %R 780488986 [pii];10.1080/00365510701408582 [doi]