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(A (R)) test (Euro-Diagnostica, Malmo, Sweden) compared to routinely used ELISA assays (Immunoscan CCPlus(A (R))-Euro-Diagnostica, Sweden, and QuantLite(A (R)) 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(A (R)) test were equivalent to the Immunoscan CCPlus(A (R)) and Quanta Lite(A (R)) 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(A (R)) results obtained using capillary blood versus serum. CCPoint(A (R)) is a novel technology that allows for a rapid accurate analysis of ACPA and diagnosis during the patient's visit in the rheumatologist office.