Urine Testing for Rheumatoid Arthritis

A non-invasive urine test for rheumatoid arthritis (RA)activity that patients could administer themselves at home could be a useful tool for disease monitoring and prognosis assessment.

In an abstract presented at the 2015 ACR Annual Meeting in San Francisco, CA, researchers described 4 urinary biomarker candidates that may be used to test for systemic inflammation. The urinary concentrations of the biomarkers they identified‑‑gelsolin, orosomucoid 1, orosomucoid 2, and soluble CD14—were determined by enzyme-linked immune-sorbent assay. The researchers also assessed disease activity in patients via disease activity score 28 (DAS28) and assessed disease severity with x-rays of patients’ hands and feet.

Levels of all 4 biomarker candidates were elevated in patients with rheumatoid arthritis and positively correlated with the status of disease activity. The authors noted that several combinations of biomarkers (especially orosomucoid 1 + orosomucoid 2 and soluble CD14 + orosomucoid 2) “efficiently represented the presence of high RA activity without the need for blood markers.”

Analysis showed that urinary level of orosomucoid 2 in particular was an independent predictor of rheumatoid arthritis progression. The authors noted that the combination of urinary orosomucoid 2 and serum C-reactive protein “synergistically increased the predictability for radiographic progression.”

Based on these results, the authors concluded that these urinary biomarkers “provide novel candidates for patient-driven measurements of RA activity at home and can shift the paradigm from blood to urine testing in the assessment of RA activity and prognosis in hospitals.”