Early detection and aggressive treatment of rheumatoid arthritis are vital in order to prevent damage to joints. To spot RA and measure its progression, rheumatologists test the blood for certain biomarkers, or biological substances – proteins, for instance – that are characteristic of RA. Although several biomarker tests – the erythrocyte sedimentation (sed) rate, the C-reactive protein (CRP), and rheumatoid factor (RF) – indicate inflammatory activity, they are fairly non-specific to RA. In other words, the tests could be positive if you have an infection or another cause for inflammation besides RA. So, the development of new biomarker tests specific to RA is important.These tests may not only allow earlier detection of RA but they also represent an advance in personalized medicine: The more specific the test, the more customized care becomes for each RA patient.

As rheumatologist Jeffrey Curtis, MD, MS, MPH, associate professor of Medicine at the University of Alabama-Birmingham and a consultant for Crescendo Bioscience, the manufacturer of Vectra DA, a new test, says, “The desire is to measure biomarkers of RA beyond [the sed rate and the CRP] that do a better job of knowing how active the RA is.”

Below are descriptions of new and emerging biomarker tests that are being used to diagnose and monitor RA disease activity

Polyglutamate Testing: A Measure of Methotrexate’s Effectiveness

What It Is: Methotrexate is one of the most commonly prescribed and effective drugs for rheumatoid arthritis. Once it enters the cells, it is converted to methotrexate polyglutamates, explains Maria I. Danila, MD, MSc, assistant professor of Medicine, Division of Clinical Immunology and Rheumatology at the University of Alabama-Birmingham.

Unless that conversion occurs, methotrexate won’t work its therapeutic magic. Because 30 to 40 percent of patients do not respond to methotrexate, and early treatment of RA is essential, the measurement of methotrexate polyglutamates in the blood may show if a person if being adequately or inadequately treated. The measurement is taken three months after someone begins taking methotrexate.

Why It’s Different. It can take months for methotrexate to work its effect, results largely gathered through a doctor’s assessment, a swollen joint count and a disease activity score. The theory is that measuring methotrexate polyglutamate levels at three months may indicate earlier whether the methotrexate is working.