A novel method for a fast diagnosis of septic arthritis using mid infrared and deported spectroscopy

To assess the ability of mid infrared deported spectroscopy to discriminate synovial fluids samples of septic arthritis patients from other causes of joint effusion.

Synovial fluids obtained from patients with clinically suspected arthritis were collected, analysed and classified according to standard diagnostic procedures as septic or non-septic. A spectroscopic analysis on synovial fluid samples was then performed using a coiled optical fiber made with chalcogenide glass. After a factorial analysis of the normalized spectra and the computation of a Fisher test used to select the most relevant components, a logistic regression model was fitted, allowing to attribute a score between 0 - non-septic -, and 1 - septic.

In a first phase, we analysed the synovial fluids from 122 different synovial fluids including 6 septic arthritis among arthritis of various origins. Septic synovial fluids were identified with a sensitivity of 95.8% and a specificity of 93.9% and an AUROC of 0.977. The analysis of an independent set of samples (n=42, including two septic arthritis) gave similar values.

Our data strongly supports the interest of mid infrared deported spectroscopy, which could be used potentially at point of care, for a rapid and easy diagnosis of septic arthritis. Now, the precision of the diagnosis must be evaluated through a multicentric study on a larger panel of patients.