Researchers discourage routine use of alpha defensin for clinical decision-making
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PHOENIX — An investigation into the preoperative and postoperative clinical utility of synovial alpha-defensin tests showed the test did not change clinical decision-making in the setting of periprosthetic joint infection, a study presented at the Orthopaedic Research Society Annual Meeting showed.
“Routine use of alpha defensin is actually not necessary in clinical practice despite high sensitivity and specificity.” Derek F. Amanatullah, MD, PhD, of Stanford University, said.
“It’s a redundant test,” he said.
Amanatullah and his colleagues came to this conclusion after they gave data for 170 patients, who were randomized, to four providers – two orthopedic surgeons and two infectious disease specialists – and asked that they draw conclusions concerning periprosthetic joint infection (PJI) based solely on the Musculoskeletal Infection Society (MSIS) criteria.
Researchers followed up with the same providers and gave them data for the same patients, who were randomized again, and this time they asked the providers to diagnose the patients for PJI based on the results of patients’ synovial alpha defensin tests.
In both instances, the providers were asked yes or no for whether each patient had a PJI.
According to Amanatullah, the orthopedic surgeons “agreed 80% of the time in the presence of a PJI, based on the MSIS criteria. If you give them alpha defensin, it’s the same.”
Similarly, the infectious disease doctors made the same diagnoses using either solely the MSIS criteria or the synovial alpha defensin test results, he said.
“It actually turns out to be that they’re getting no new information by applying the test,” Amanatullah said.
For this reason, he noted the inclusion of the alpha defensin test in the MSIS criteria should perhaps be reconsidered.
“We need independent tests. So, we abandoned the use of this test at our center at Stanford and we only use it in the setting of indeterminant initial aspirations, as a second-line test,” Amanatullah said. – by Susan M. Rapp
Reference:
Amanatullah DF, et al. Poster 515. Presented at: Orthopaedic Research Society Annual Meeting; Feb. 8-11, 2020; Phoenix.
Disclosure: Amanatullah reports he receives IP royalties and is a paid consultant for Exactech; has stock or stock options with QT Ultrasounds and Recoup Fitness; receives research support from Reflexion, Roam Robotics and Sparta Health Science; is a paid consultant for and receives research support from Stryker; and receives publishing royalties and financial or material support from WebMD.