Utility of Plasma Protein Biomarkers and Mid-Infrared Spectroscopy for Diagnosing Fracture-Related Infections: A Pilot Study

Abstract

Objectives: To compare a large panel of plasma protein inflammatory biomarkers and mid-infrared (MIR) spectral patterns between patients with confirmed fracture related infections (FRIs) and controls without infection. Design: Prospective case-control. Setting: Academic, level 1 trauma center. Patients: Thirteen patients meeting confirmatory FRI criteria were matched to 13 controls based on age, time after surgery, and fracture region. Intervention: Plasma levels of 49 proteins were measured using enzyme-linked immunosorbent assay (ELISA) techniques. Fourier transform infrared (FTIR) spectroscopy of dried films was used to obtain MIR spectra of plasma samples. Main Outcome Measurements: Plasma protein levels and MIR spectra of samples. Results: Multivariate analysis-based predictive model developed utilizing ELISA-based biomarkers had sensitivity, specificity, and accuracy of 69.2±0.0%, 99.9±1.0%, and 84.5±0.6%, respectively, with PDGF-AB/BB, CRP, and MIG selected as the minimum number of variables explaining group differences (P<0.05). Sensitivity, specificity, and accuracy of the predictive model based on MIR spectra were 69.9±6.2%, 71.9±5.9%, and 70.9±4.8%, respectively, with six wavenumbers as explanatory variables (P<0.05). Conclusions: This pilot study demonstrates the feasibility of using a select panel of plasma proteins and FTIR spectroscopy to diagnose FRI. The preliminary data suggest that measurement of these select proteins and MIR spectra may be potential clinical tools to detect FRI. Further investigation of these biomarkers in a larger cohort of patients is warranted.