Abstract: Objective　To investigate the significance of cross-linked carboxyterminal telopeptide region of type Ⅰ collagen (ICTP)， matrix metalloproteinase-3 (MMP-3)， anti-cyclic citrullinated peptide (CCP) antibody， rheumatoid factor (RF) and rheumatoid arthritis(RA) activity in the early diagnosis of RA.  Methods　The enzyme-linked immunosorbent assay(ELISA) was used to determine the serum samples of 213 patients with RA (early RA group: 92 cases and medium-and long-term RA group: 121 cases)， 43 patients with non-RA associated and immune diseases and 40 healthy controls. The serum ICTP， MMP-3 and anti-CCP antibody were determined. The serum RF was determined by immunoturbidimetry.  Results　The optimal cut-off values of ICTP， MMP-3 and anti-CCP antibody in the diagnosis of early RA were 3.21 μg/L， 67.45 ng/mL， 15.45 U/mL and 12.35 U/mL. The sensitivities were 74.0%，63.4%，52.4% and 55.3%， and the specificities were 95.5%， 81.8%， 95.5% and 90.9%. RF and anti-CCP antibody were higher in the RA group than in the healthy control group and the non-RA group (P＜0.01). ICTP， MMP-3 and RF in the non-RA group and the healthy control group had statistical significance ( P＜0.01). ICTP in early RA and non-RA  group had no statistical significance (P＞0.05). The ICTP， MMP-3， anti-CCP antibody and RF of X ray staging Phase Ⅰ had statistical significances with those staging Phase Ⅱ， Ⅲ and Ⅳ(P＜0.05， P＜0.01). The ICTP， MMP-3 and anti-CCP antibody of Phase Ⅱ with those of Phase Ⅲ and Ⅳ had statistical significance (P＜0.05， P＜0.01). The RF among Phase Ⅱ， Ⅲ and Ⅳ had no statistical significance (P＞0.05). Conclusions　The simultaneous detection of ICTP， MMP-3， anti-CCP antibody and RF can improve accuracy and reduce missed diagnosis. Dynamic combination detection can monitor effectively the progression of RA.

Key words: Cross-linked carboxyterminal telopeptide region of type Ⅰ collagen, Matrix metalloproteinase-3, Anti-cyclic citrullinated peptide antibody, Rheumatoid factor, Rheumatoid arthritis