A novel bedside test for ACPA: the CCPoint test is moving the laboratory to the rheumatologist's office

Rheumatoid Arthritis (RA) is an autoimmune destructive joint disease affecting 1 % of the general population. In recent years, the benefits of identifying RA at an early stage and initiating therapy before joint damage occurs have been acknowledged. An elevated anti-citrullinated peptide antibody (ACPA) level serves as a marker for the early diagnosis of RA. Often the diagnosis is delayed because conventional methods of antibody detection require referral to a specific laboratory. In the current study, we determined the diagnostic accuracy of a new lateral flow point-of-care kit available for ACPA detection in the rheumatologist office. The presence of ACPA was determined by the visually read, qualitative rapid CCPoint^® test (Euro-Diagnostica, Malmö, Sweden) compared to routinely used ELISA assays (Immunoscan CCPlus^®-Euro-Diagnostica, Sweden, and QuantLite^® CCP3-INOVA Diagnostics Inc., USA), in the sera of 184 patients: early RA(n = 38), established RA (n = 84), inflammatory arthritis(n = 34) and systemic lupus erythematosus (SLE) (n = 28). ACPA was detected in 18/38(47 %), 53/84(63 %), 2/34(6 %) and 2/28(7 %) of patients with early RA, established RA, inflammatory arthritis and SLE, respectively. The sensitivity and specificity, negative and positive predictive values of the CCPoint^® test were equivalent to the Immunoscan CCPlus^® and Quanta Lite^® CCP3 ELISA assays. Correlation between ACPA positive results detected in the different assays was 97 %, while negative agreement reached 98 %. Excellent correlation (100 %) was observed between CCPoint^® results obtained using capillary blood versus serum. CCPoint^® is a novel technology that allows for a rapid accurate analysis of ACPA and diagnosis during the patient's visit in the rheumatologist office.