CRP and rheumatoid arthritis: Our observation was compatible with the results from previous studies, in which RA patients with normal CRP levels were recruited.20–22 The most relevant finding of our study was that we propose an optimal cut-off level of 115.9 ng/ml, which can help for the differentiation of ultrasonographically active RA patients, not only from healthy controls, but also from RA patients with normal CRP levels.