Specimen Collection

3.5 mL SST Serum (Preferred)

4 mL Plain Blood

EDTA or CPD plasma is not suitable. Microcollect 2 plain tubes (minimum).

500 uL Microsample Serum
Reference Intervals

Uncertainty of Measurement: 12%

Abnormal - Units: Units

Age Range	Either Sex
All	>= 20[1]

[1] Levels of CCP antibodies in this interval are considered positive.
Turnaround Time: Within 1 week

Turnaround time dependent on number of requests, but usually analysed twice a week.

Diagnostic Use and Interpretation

Rheumatoid Arthritis (RA) is one of the most common systemic autoimmune diseases. The aetiology of the disease is unknown. Approximately 0.5% of the world population is affected, and twice as many women as men get the disease. Until recently, the only serological test routinely used was the determination of the presence of rheumatoid factors (RF) in serum. RF are antibodies directed to the Fc region of immunoglobulins of the IgG class. RF can be of the IgM, IgG and IgA immunoglobulin classes. The presence of IgM RF is a hallmark of RA, found in approximately 50-90% of these patients. However, IgM RF are found in people with infections, other autoimmune disease, and some healthy individuals. IgG RF are less sensitive but more specific for RA than IgM RF.

It is important for disease management to diagnose and treat people with RA as early possible. It has been known for many years that anti-perinuclear autoantibodies, also called anti-keratin, are found in people with RA. Recently it was discovered that these autoantibodies recognise an epitope that contains the deimidated form of arginine called cirulline. A circular peptide containing citrulline called CCP (Cyclic Citrullinated Peptide) was found to be better at discriminating RA patients than either the perinuclear autoantibody test or the test for rheumatoid factor. Additionally, RA patients with anti-CCP may progress to a more severe disease than those who do not have anti-CCP. In published literature, approximately 70% of patients with RA are positive for anti-CCP, while only about 2% of healthy blood donors and disease control subjects are positive. Thus, both negative and positive results on this test have high predictive values. A recent study found citrullinated proteins in the joints of patients with RA, but not in joints form health volunteers. These results lend a theoretical basis for the presence of anti-CCP in RA patients and a possible pathogenic role for these antibodies.

References

1. INOVA CCP product insert

Contact Information

For further information contact the laboratory, (09) 307 4949 ext 22103 or:
Associate Professor Rohan Ameratunga , Immunopathologist: Locator 93-5724,

Dr Richard Steele , or The LabPLUS Immunology Team

Last updated at 11:31:44 20/02/2019