Different biomarkers (miRNAs, CRP, rheumatoid factor, ACPA) associated with rheumatoid arthritis have been described, paying attention to the optical-sensing techniques (fluorescence, absorbance, different types of resonances, interferometry or spectroscopy) proposed in the literature for its detection as well as providing a justification for their use as RA biomarkers. This evidence concerns the gene PRTN3 and rheumatoid arthritis.