Osteoarthritis (OA) is the most prevalent degenerative joint disease worldwide, which causes pain, loss of joint function and declined quality of life, and ranks as the leading cause of disability among individuals aged over 60 years. In China, the number of patients with osteoarthritis is projected to exceed 200 million by 2044, resulting in a continuously growing demand for medical resources and escalating economic burden.Nevertheless, the lack of effective biomarkers for early diagnosis leads to advanced disease conditions at the time of initial medical consultation and delayed treatment. This project intends to collect blood samples from OA patients and suspected patients in the orthopedic outpatient department of a tertiary hospital. Diagnostic and differential diagnostic tests will be adopted to verify the clinical application value of previously reported candidate biomarkers, so as to screen out biomarkers with favorable validity and reliability. The research findings are expected to provide data support and theoretical basis for the early prevention, early diagnosis and individualized intervention of osteoarthritis.