Work

Use of Synofast® in routine rheumatology practice: diagnostic performance and impact on management of an acute arthritis

Year: 2025

Type: article

Abstract: BACKGROUND: Septic arthritis (SA) is a rare but serious disease. There is no reliable marker for rapid diagnosis. Synofast® is a new device that analyses synovial fluid and can accurately rule out SA within 15 minutes. OBJECTIVE: To evaluate the diagnostic performance of Synofast® in routine practice in patients with suspected SA and to assess its impact on patient care. METHOD: This was a monocentric prospective study of patients with acute arthritis of possible septic origin. In addition to the usual blood and synovial bacteriological tests, a drop of synovial fluid was taken for the Synofast® test, which provides three SA risk probabilities: "low", "possible" or "high". The physician recorded the management he would have given before the test and the management he actually gave after the test, knowing the diagnostic performance reported in previous studies. RESULTS: Over one year, 43 patients were included, of whom eight had SA (18.6%). Sensitivity, negative predictive value (PV) and negative likelihood ratio (LR) were respectively of 75%, 93% and 0.32 when analysing for "high" and "possible" septic risk while specificity, positive PV and positive LR were respectively of 94%, 67% and 8.75 when analysing for "high" septic risk only. The test helps to avoid hospitalisations in 1/29 patients and to defer antibiotic in 1/7 patients. Follow-up and drug management remained unchanged in 95% and 89% of patients, respectively. CONCLUSION: Synofast® seems to be a valuable tool for the exclusion of SA. The results need to be confirmed in a larger population, especially the impact on management.

Source: Revista Brasileira de Reumatologia

DOI: 10.1186/s42358-025-00506-y