Portable Mid-Infrared Spectroscopy Combined with Chemometrics to Diagnose Fibromyalgia and Other Rheumatologic Syndromes Using Rapid Volumetric Absorptive Microsampling

Abstract

The diagnostic criteria for fibromyalgia (FM) have relied heavily on subjective reports of experienced symptoms coupled with examination-based evidence of diffuse tenderness due to the lack of reliable biomarkers. Rheumatic disorders that are common causes of chronic pain such as rheumatoid arthritis, systemic lupus erythematosus, osteoarthritis, and chronic low back pain are frequently found to be comorbid with FM. As a result, this can make the diagnosis of FM more challenging. We aim to develop a reliable classification algorithm using unique spectral profiles of portable FT-MIR that can be used as a real-time point-of-care device for the screening of FM. A novel volumetric absorptive microsampling (VAMS) technique ensured sample volume accuracies and minimized the variation introduced due to hematocrit-based bias. Blood samples from 337 subjects with different disorders (179 FM, 158 non-FM) collected with VAMS were analyzed. A semi-permeable membrane filtration approach was used to extract the blood samples, and spectral data were collected using a portable FT-MIR spectrometer. The OPLS-DA algorithm enabled the classification of the spectra into their corresponding classes with 84% accuracy, 83% sensitivity, and 85% specificity. The OPLS-DA regression plot indicated that spectral regions associated with amide bands and amino acids were responsible for discrimination patterns and can be potentially used as spectral biomarkers to differentiate FM and other rheumatic diseases.

Surface Enhanced Raman Spectroscopy Combined With Multivariate Analysis for Fingerprinting Clinically Similar, Fibromyalgia and Long-COVID Syndromes

“…For blood sample extraction, a procedure used in previous studies [6,16,27,28] based on washedfilter-membrane was incorporated. Amicon ® Ultra centrifugal filters (Merck Millipore, Billericia, MA, USA) with 10 kDa cut-off were used to fractionate low-molecular-weight (LM) solutes from the blood samples.…”

“…Before extraction, the filters were rinsed with 3 mL milli-Q water, followed by centrifugation at 4000 rpm for 10 min (Figure 1). This step ensured the removal of glycerol present on filter membranes that could produce artifacts in the SERS spectra and interfere with multivariate analysis [16].…”

“…Fibromyalgia (FM) is a chronic central sensitivity syndrome characterized by augmented pain processing at generalized body sites, affecting nearly 5% of the world's population, predominantly women [13][14][15]. FM presents as a multimorbid clinical condition, often accompanied by sleep disturbances, mood disorders, chronic fatigue, intestinal irritability, migraines, and temporomandibular joint disorder [16]. FM is characterized by the amplification of neuronal signals leading to central sensitization, resulting from an imbalance in the central nervous system and neuroendocrine function [17].…”

“…Soft Independent Modeling of Class Analogies (SIMCA), a supervised classification methodology where the syndrome status corresponding to each spectrum is provided, along with the spectral data. SIMCA constructs a classification model by carefully assessing the differences in spectral information among different groups, potentially originating from associated biomarkers [16].…”

“…Our research group has been extensively assessing the vibrational spectroscopic characteristics of FM and related rheumatologic conditions (rheumatoid arthritis (RA), chronic low back pain (CLBP), systemic lupus erythematosus (SLE), and osteoarthritis (OA)) over the past decade [6,16,19,[26][27][28]. We have identified the potential of portable mid-infrared (MIR), MIR micro spectroscopy, FT-Raman microspectroscopy and SERS in diagnosing FM from similar symptomatic syndromes (RA, SLE, OA, CLBP).…”