Blood levels of a protein called 14-3-3eta are better indications of early-stage RA than any test currently on the market.

A new study shows that a specific blood marker can help doctors identify rheumatoid arthritis (RA) in its early stages. This is good news for doctors who want to detect and treat RA early. Early treatment can help prevent joint damage and disability. The study was published in the Journal of Rheumatology.

The researchers found that high levels of a protein called 14-3-3eta in the blood are a better indicator of RA than antibody-serum testing. Traditional antibody-serum tests include rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA) testing.

Scientists compared the various tests in 234 patients who had early-stage RA and established RA. They also looked at 385 patients in control groups. The control groups included people who were healthy, patients with osteoarthritis, and patients with other autoimmune diseases.

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In the study, 64 percent of patients diagnosed with early-stage RA tested positive for 14-3-3eta. The ACPA test identified 59 percent, while the RF test identified only 57 percent. The tests identified 78 percent of early-stage RA patients and 96 percent of patients with established RA when the scientists used all three markers.

The researchers say that testing for the protein is more effective in detecting patients who have RA despite negative RF and ACPA tests. In those patients, the 14-3-3eta test spotted 21 percent of patients with early RA and 67 percent with established RA. False negative test results can delay diagnosis and treatment.

“While previous research established that 14-3-3eta is found in higher levels in patients with RA than healthy patients, our study demonstrates the clinical usefulness of 14-3-3eta for improved diagnostic capacity of testing for early RA,” said Dr. Walter Maksymowych, lead study author and a medical research professor at the University of Alberta in Canada, in a press statement.

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“Combined testing of 14-3-3eta with established markers will help provide physicians with more definitive diagnostic information and help facilitate early treatment with disease modifying anti-rheumatic drugs,” Maksymowych added.

The researchers also found that levels of the protein were higher in those with early and established RA, compared to healthy people and those in all of the control groups. This means that the biomarker may help tell RA patients apart from people with other autoimmune diseases.

14-3-3eta levels were also higher in those with early-stage RA than in those with osteoarthritis. This means the test may help primary care doctors tell who should be referred to a rheumatologist for treatment.

“It would be extremely helpful if this turns out to be a useful test clinically,” said Dr. Paul Sufka, a rheumatologist practicing in Minnesota. “Right now, it appears that this will be helpful in identifying patients with rheumatoid arthritis sooner, which would result in earlier treatment.”

Sufka noted that the study only included a few hundred patients. The test will need to be studied more to see if it could be beneficial for more people.

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