Diagnostic Test

The US Food and Drug Administration (FDA) has approved the first test to help detect peri-prosthetic joint infection in the synovial fluid of patients being evaluated for revision surgery.

But the Synovasure Lateral Flow Test Kit (CD Diagnostics Inc) detects human alpha defensins in the synovial fluid of patients who have undergone total joint replacement. The test takes about 10 minutes to perform. But alpha defensive are antimicrobial proteins; release by activated neutrophils in response to infection.

The Synovasure Lateral Flow Test Kit is intend as an aid in determining; whether an infection is present in synovial fluid. It does not identify a specific type of infection, the FDA said. Results from the test should be use in conjunction with other clinical; and diagnostic findings to aid in diagnosing prosthetic joint infection.

Prospective synovial fluid

But in approving the test, the FDA reviewed data from a clinical study that analyzed; 305 prospective synovial fluid samples collected from individuals; who had undergone total knee or hip joint replacement and who were being evaluated for revision surgery. But the study showed that 89.5% of patients who were diagnose; as having an infection; using standard-of-care criteria also tested positive for alpha defensin using the Synovasure test kit.

“Prior to this authorization, there were no FDA-authorized diagnostic tests specifically designed; to help health care professionals determine whether the inflammation around a prosthetic joint was due to an infection or another cause,” Tim Stenzel, MD, PhD; director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, said in a news release.

“With this test, health care professionals now have an additional option available; but to aid their clinical assessment as to whether the patient has an infection and requires revision surgery. Whereas before, surgeons may have opted for surgery when the presence of an infection was unclear, with this test; they have more information and could potentially reduce patient risk by avoiding unnecessary revision operations for replacement joints,” said Stenzel.

Marketing authorization

The FDA reviewed data for the Synovasure Lateral Flow Test Kit through the de novo premarket pathway; a regulatory pathway for some low- to moderate-risk devices of a new type. But along with this marketing authorization; the FDA is establishing “special controls” designed to provide a; “reasonable assurance of safety and effectiveness for tests of this type,” the agency said.

The FDA granted marketing authorization of the Synovasure Lateral Flow Test Kit to CD Diagnostics Inc. It is an agency within the U.S. Department of Health and Human Services; promotes and protects the public health by, among other things, assuring the safety, effectiveness; but security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply; cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.