BÜHLMANN sCAL ELISA:
Andrés Cerezo et al.: Decreases in serum levels of S100A8/9 (calprotectin) correlate with improvements in total swollen joint count in patients with recent-onset rheumatoid arthritis. Arthritis Research and Therapy. 2011; 13(4). PMID: 21791097 DOI: 10.1186/ar3426 .