The U.S. Food and Drug Administration has approved CD Diagnostics Inc.'s test to help in the detection of infections around a joint replacement for certain patients.
CD Diagnostics' Synovasure Lateral Flow Test Kit is now approved as an aid to detect periprosthetic joint infection in the joint lubricating fluid of patients being evaluated for surgery to replace or compensate for a failed implant, or revision surgery.
There were previously no FDA-authorized diagnostic tests specifically designed to help healthcare professionals determine whether inflammation around a prosthetic joint was due to an infection or another cause, according to a May 23 news release.
The test kit takes about 10 minutes to detect proteins called human alpha defensins — released by white blood cells in response to infection — in the joint lubricating fluid, called synovial fluid, of patients with a total joint replacement. According to the FDA, the test kit is intended only as an aid to determine whether an infection exists in the synovial fluid and is not meant to identify a specific type of infection.
For the approval, the FDA reviewed data from a study of 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 found that 89.5% of subjects with an infection diagnosis based on standard of care criteria also tested positive for the alpha defensin proteins with the Synovasure Lateral Flow Test Kit.
In addition, the FDA is establishing special controls to determine the requirements for showing the safety and effectiveness of tests to detect and measure nonmicrobial substances to help in detecting and identifying localized human infections. These special controls, along with general controls, provide a reasonable assurance of safety and effectiveness for these tests.