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FDA Approves CD Diagnostics' Test for Prosthetic Joint Infections

NEW YORK (360Dx) – The US Food and Drug Administration on Thursday granted de novo premarket approval for CD Diagnostics' Synovasure Lateral Flow Test Kit used in the detection of periprosthetic joint infection, which occurs around a joint replacement.

The infections manifest in the synovial fluid of patients being evaluated for revision surgery to replace or compensate for a failed implant. 

The Synovasure Lateral Flow Test Kit detects human alpha defensins proteins in the synovial fluid of patients with a total joint replacement in about 10 minutes. Alpha defensins are antimicrobial proteins released by activated neutrophils, or white blood cells, in response to infection.

Physicians typically evaluate patients for potential infections using X-ray images or laboratory analysis of joint fluid that can take days for results.

An FDA-authorized diagnostic test had not been previously available to help healthcare professionals determine whether the inflammation around a prosthetic joint was due to an infection or another cause, Tim Stenzel, director of the FDA's Office of In Vitro Diagnostics and Radiological Health, said in a statement.

Surgeons may have previously opted for an operation when the presence of an infection was unclear, but with this test, they have more information and could potentially reduce patient risk by avoiding unnecessary revision procedures for replacement joints, he said.

The FDA reviewed data from a clinical study that analyzed 305 prospective synovial fluid samples collected from individuals with a total knee or hip joint replacement who were being evaluated for revision surgery. The study showed that 89.5 percent of subjects with an infection diagnosis based on standard-of-care criteria were also identified as positive for alpha defensin by the Synovasure Lateral Flow Test Kit.  

Claymont, Delaware-based CD Diagnostics markets biomarker-based immunoassays.

Its first product, Synovasure PJI for joint infection, is available as a laboratory-developed test in the US and CE marked in both ELISA plate and lateral flow formats for use in Europe.