Assay

Cyclic Citrullinated Peptide Antibodies (CCP)

Key Words

Anti CCP abs,  CCP

Specimen Collection

Serum (brown)

Turnaround time

7 days

Test indications

Antibodies against cyclic citrullinated peptides (CCP) may be used in the diagnosis of rheumatoid arthritis (RA). CCP antibodies are now known to be the same as several other autoantibodies which were thought to be associated with RA including antiperinuclear factor, filaggrin antibodies and keratin antibodies. Manufacturer’s data for this second-generation assay suggests that positive results (>10 U/ml) have approximately 80-88% sensitivity and >95% specificity for RA. It is important to appreciate that the test does not indicate disease activity, and is unlikely to change with time, so does not need repeating in the same individual. CCP antibodies are useful when there is diagnostic difficulty in making a firm diagnosis of RA, but are not necessary to measure in clear-cut classical rheumatoid arthritis. Negative CCP antibodies in RF-negative RA patients who have responded to treatment, may indicate that a trial of withdrawal of therapy is appropriate.

Methodology

Enzyme immunoassay

Interferences

No known methodological interferences

Reference Range

Negative   <7 U/mL

Equivocal  7-10 U/mL

Positive     >10 U/mL

Analytical error

Contact the Laboratory (x8454)

Reference change value

N/A

Minimum retesting interval

CCP requests made within 5 years of a previous request on a patient are intervened