(HealthDay News) – A rapid biomarker-based method using blood samples is able to accurately differentiate patients with fibromyalgia syndrome (FM) from those with rheumatoid arthritis (RA) or osteoarthritis (OA), according to a study published in the Aug. 21 issue of Analyst.

Kevin V. Hackshaw, MD, from The Ohio State University in Columbus, and colleagues examined the ability of mid-infrared microspectroscopy (IRMS) to diagnose FM and to differentiate patients with FM from those with OA and RA. Blood samples were collected from 14 patients with FM, 15 with RA, and 12 with OA; following preparation, spectra were collected using IRMS. The samples also underwent metabolomic analysis.

The researchers found that IRMS was able to classify subjects based on spectral information, with no misclassifications among FM and RA or OA patients. Among subjects, the interclass distances were 15.4 (FM vs. RA), 14.7 (FM vs. OA), and 2.5 (RA vs. OA). In metabolomic analysis, RA and OA groups were metabolically similar, while there were distinct biochemical differences identified in the FM group. Changes in tryptophan catabolism pathways that differentiated patients with FM from those with RA or OA were identified in both approaches.

“While both methods were able to obtain informative results using bloodspot samples, the IRMS approach differentiated FM subjects from the RA and OA groups with zero misclassifications (100% accuracy), whereas the accuracy of the metabolomics approach was 75%,” the authors write. “Additionally, the cost of the IRMS analysis was lower than that of the metabolomics approach.”

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