Third generation anti-citrullinated peptide antibody assay is a sensitive marker in rheumatoid factor negative rheumatoid arthritis.

Abstract

INTRODUCTION:

We compared 2 anti-citrullinated protein antibody (ACPA) assays using a routine patient cohort.

METHODS:

Two-hundred ninety-five sera were collected from patients for whom ACPA was ordered and tested for ACPA by QUANTA Lite® CCP 3 (INOVA Diagnostics, Inc., San Diego) and EliA® CCP (CCP, Phadia, Germany). Rheumatoid factor (RF) was determined using Quantex RF(II) (Biokit, Spain).

RESULTS:

Acceptable qualitative (96.6%, kappa=0.93) and quantitative agreements (Spearman rho=0.77; p<0.0001) were observed between the two ACPA assays. Nine samples were CCP3+/CCP2- and one sample was CCP2+/CCP3-. Of the 9 CCP3+/CCP2- patients, 6 (66.7%) had RA, one patient had ankylosing spondylitis, one osteoarthritis and one psoriatic arthritis. The CCP3-/CCP2+ patient had juvenile RA. At the manufacturer's cut-offs, the sensitivities and specificities were 77.3%/98.1% (CCP2), 81.6%/96.8% (CCP3) and 65.2%/89.6% (RF), respectively. At 98.7% specificity level, the sensitivities in the total cohort were 59.6% (CCP2) and 69.5% (CCP3) while the sensitivities in the RF-negative group were 49.0% (CCP2) and 57.1% (CCP3). In the RF-negative group, sensitivities for patients with a disease duration of ≤ 5years were 38.7% (CCP2) and 51.6% (CCP3).

CONCLUSION:

Discrimination between RA and non-RA patients was better using CCP3, most pronounced in RF-negative RA.

• Authors: Andreas Swart, Rufus W Burlingame, Irmgard Gürtler, Michael Mahler
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 414 Pg. 266-72 (Dec 24 2012) ISSN: 1873-3492 [Electronic] Netherlands
• PMID: 23022338 (Publication Type: Journal Article)
• Copyright: Copyright © 2012 Elsevier B.V. All rights reserved.

Chemical References

• Autoantibodies
• Biomarkers
• Peptides, Cyclic
• cyclic citrullinated peptide

Topics

• Arthritis, Rheumatoid (diagnosis, immunology)
• Autoantibodies (blood, immunology)
• Biomarkers (blood)
• Female
• Humans
• Immunoassay
• Male
• Middle Aged
• Peptides, Cyclic (blood, immunology)
• Sensitivity and Specificity