TY - JOUR T1 - Likelihood ratios as a function of antibody concentration for anti-cyclic citrullinated peptide antibodies and rheumatoid factor JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis SP - 287 LP - 289 DO - 10.1136/ard.2007.085597 VL - 68 IS - 2 AU - X Bossuyt AU - D Coenen AU - S Fieuws AU - P Verschueren AU - R Westhovens AU - N Blanckaert Y1 - 2009/02/01 UR - http://ard.bmj.com/content/68/2/287.abstract N2 - Anti-cyclic citrullinated peptide (CCP) antibodies and rheumatoid factor (RF) are recommended screening tests for rheumatoid arthritis.1 In a meta-analysis,2 the sensitivity of anti-CCP (67%) for diagnosing rheumatoid arthritis was comparable to the sensitivity of RF (69%).2 The specificity of anti-CCP for rheumatoid arthritis (95%) was higher than the specificity of RF (85%).2 Consequently, the positive likelihood ratio was higher for anti-CCP (12.46) than for RF (4.86).2Studies that addressed the clinical usefulness of anti-CCP used a single cut-off value and, hence, likelihood ratios were calculated based on a single cut-off. In the present letter, we illustrate how likelihood ratios for anti-CCP and RF … ER -