The first blood test for early-stage osteoarthritis could soon be developed, say researchers who suggest the biomarker they have identified can detect the painful joint condition before bone damage occurs. Share on Pinterest The study shows it is possible to detect and distinguish osteoarthritis and rheumatoid arthritis in the early stages with a single blood test. The research, led by the University of Warwick in the UK, is published in the journal Scientific Reports. The authors found that testing for citrullinated proteins (CPs) in the blood could lead to osteoarthritis (OA) being diagnosed years before physical symptoms emerge. They also found that CPs may serve as a reliable way to detect early-stage rheumatoid arthritis (RA). Lead researcher Dr. Naila Rabbani, reader of experimental systems biology at Warwick, says: “This is a remarkable and unexpected finding. It could help bring early-stage and appropriate treatment for arthritis, which gives the best chance of effective treatment.” Dr. Rabbani and colleagues note that while there are established biomarker tests for early-stage RA, there are none for OA and suggest their findings could lead to a test for both that also distinguishes between the two.

CPs elevated in patients with early-stage OA, RA Osteoarthritis is a joint disease associated with aging. It develops when the protective cartilage layer inside joints wears away because of continually being stressed over a person’s lifetime. This type of arthritis normally affects the knees, hips, fingers and lower spine and rarely strikes before the age of 60. The World Health Organization (WHO) estimate that about 9.6% of men and 18.0% of women over 60 have symptomatic osteoarthritis. RA is a chronic systemic disease that affects not only the joints but also tendons, connective tissue, muscle and fibrous tissue. It is a disabling condition that often causes pain and deformity and tends to strike between the ages of 20 and 40. According to WHO, RA affects up to 3% of the global population. The disease is more common in women and in developed countries, where around half of people who develop it are not able to have a full-time job within 10 years of onset. For their study, the researchers developed a method based on mass spectrometry to measure CPs in body fluids. They found that CPs were elevated in patients with early-stage OA and early-stage RA. Previous studies had already established that people with RA had antibodies to CPs, but these have not been found in early-stage OA.