Alpha Defensin, Synovial Fluid, LFA

Specimen source and type of joint are required. If not obtained from a prosthetic joint, testing will be canceled.

Ask-at-Order-Entry questions must be answered. "Not Given" or "NG" answers are not acceptable. Freshly collected synovial fluid only.

Note: Synovial fluid obtained after repeated aspirations within a short period might lead to false-negative results due to the lack of buildup of alpha defensin.

The use of synovial fluid diluted with saline, blood, contrast agent, or any substances injected into the joint may lead to false-negative results.

Detection of alpha defensins 1-3, human host response proteins, in synovial fluid of adults with a total joint replacement who are being evaluated for revision surgery.

Diagnosis of prosthetic joint infections (PJI) may be challenging in certain clinical scenarios. Multiple societies have defined criteria for establishing the presence of a PJI, including results from laboratory tests, clinical findings, and tissue histopathology. The challenge, however, is that results of these tests are frequently not available at the time of or after surgery. As an alternative, determining the cell count and differential on synovial fluid are frequently used biomarkers for PJI, however, there is a lack of consensus on the optimal thresholds to use for a PJI diagnosis. Additionally, cell count and differential results require clinician interpretation as laboratories do not report abnormal levels correlating with PJI. Alpha defensins are antimicrobial peptides released by activated neutrophils in response to infection and served as part of the host-defense innate immune system with broad antimicrobial activity against gram-positive and gramnegative bacteria, mycobacteria, fungi, and viruses. The presence of alpha defensins in synovial fluid may therefore, be used by clinicians as a marker of PJI. Detection of alpha defensins 1-3, human host response proteins, in synovial fluid of adults with a total joint replacement who are being evaluated for revision surgery.