What Is the Multibiomarker Disease Activity Test?
Learn about this advanced RA blood test and what it’s used for.
If you have rheumatoid arthritis (RA), your rheumatologist may conduct different types of tests to gauge your disease activity and see how well your medications are working. These results give your doctor information that guides treatment decisions.
One mode of testing looks at your blood for biomarkers of inflammation linked to RA. Most biomarker tests look at only one factor, such as erythrocyte sedimentation rate (ESR or “sed rate”) or C-reactive protein (CRP) level. A relatively new test called the multibiomarker disease activity (MBDA, called Vectra DA commercially) test checks 12 proteins, hormones and growth factors linked to RA. About 50 percent of rheumatologists in the U.S. have used it, according to a spokesperson for the manufacturer, Crescendo Bioscience.
But do more measurements provide more insight? Sometimes.
When Could MBDA Help?
According to research published in the journal Rheumatology or presented at the 2015 American College of Rheumatology (ACR) annual meeting, the MBDA test may help in these scenarios:
- A high MBDA score was able to predict with more accuracy than traditional measures whether a person’s RA was at high risk of progressing within the year. Knowing how aggressive the disease is could prompt more or less intensive therapy.
- Patients who are in stable remission may wish to taper or stop their disease-modifying antirheumatic drugs (DMARDs) – but nobody wants to risk having a flare. A single-biomarker test, the anti-citrullinated protein antibody (ACPA) test, correctly predicts risk of relapse in about 30% of patients. Adding the MBDA score to ACPA results can correctly predict flare risk in more than 80% of patients. A second study showed MBDA score could help predict flare risk in patients wanting to taper off an anti-TNF biologic.
- When methotrexate doesn’t control a patient’s disease, a doctor will typically add other medications. Study results showed patients with high MBDA scores did better with methotrexate plus a biologic, while those with lower scores did better on methotrexate along with sulfasalazine and hydroxychloroquine (triple therapy).
Not the Only Measure
But the MBDA is not a test you necessarily need. According to the ACR, there were more than 60 ways to test RA disease activity in 2012.
According to Lou Bridges Jr., MD, PhD, director of the division of clinical immunology and rheumatology at University of Alabama at Birmingham, “The most widely used and validated measure is the [disease activity score] DAS28, which includes the provider’s examination of 28 joints for assessment of the number that are tender and swollen, the patient’s assessment of his or her global health, and measures of inflammation such as C-reactive protein or erythrocyte sedimentation rate.”
Composite measures like the DAS28 are comprehensive and quick to obtain but can be somewhat subjective, says Dr. Bridges. “Measurements that rely only on blood biomarkers are more objective but also more expensive, and results take time,” he says. Dr. Bridges, who notes that the MBDA test is covered by Medicare but not some private insurers, says he uses more traditional composite tests along with measures of CRP and ESR.
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