First blood test for chronic joint disease in the offing

The first blood test to detect osteoarthritis (OA) - the most common form of arthritis - could soon be available as researchers have identified a biomarker linked to both rheumatoid and osteoarthritis diseases.

Osteoarthritis causes pain, swelling and reduced motion in your joints. It can occur in any joint, but usually it affects your hands, knees, hips or spine.

The findings, published in the journal Nature Scientific Reports, could potentially lead to patients being tested for osteoarthritis and diagnosed several years before the onset of physical symptoms.

Whilst there are established tests for rheumatoid arthritis (RA), the newly identified biomarker could lead to one that can diagnose both rheumatoid arthritis and osteoarthritis (OA).

"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," said lead researcher Naila Rabbani from the University of Warwick, England.

The researchers' focus was citrullinated proteins (CPs) -- a biomarker suspected to be present in blood of people with early stage RA.

The researchers found for the first time increased CPs levels in both early-stage OA and RA.

They then produced an algorithm of three biomarkers, CPs, anti-CP antibodies along with the bone-derived substance, hydroxyproline.

Using the algorithm, the researchers found that with a single test, they could potentially detect and discriminate between the major types of arthritis at the early stages, before joint damage has occurred.

The ability to discriminate between RA and OA could provide a number of benefits to patients, including early diagnosis.

"This discovery raises the potential of a blood test that can help diagnose both RA and OA several years before the onset of physical symptoms," Rabbani noted.