This 2017 systematic review and meta-analysis of 33 studies evaluated 13 synovial fluid biomarkers for diagnosing periprosthetic joint infection (PJI) after total hip or knee arthroplasty. The study used the diagnostic odds ratio (DOR) to rank test performance and determine which single biomarker best identifies PJI.
Before this meta-analysis, synovial aspiration for PJI workup was dominated by culture and cell count — tests with meaningful limitations. Culture is slow, affected by prior antibiotics, and now confirmed to have sensitivity of only 0.62.
When you aspirate a painful THA or TKA, alpha-defensin gives you the highest diagnostic accuracy of any single synovial biomarker. And critically, it is not affected by prior antibiotic administration. Pair it with leukocyte count, PMN%, LE, and synovial CRP to build a diagnostic battery.
Remember: even a test with 97% sensitivity and 96% specificity can have a PPV of 0.3 if your patient population has low PJI prevalence. Always interpret results in clinical context, not in isolation.
This 2017 systematic review and meta-analysis of 33 studies evaluated 13 synovial fluid biomarkers for diagnosing periprosthetic joint infection (PJI) after total hip or knee arthroplasty. The study used the diagnostic odds ratio (DOR) to rank test performance and determine which single biomarker best identifies PJI.
Before this meta-analysis, synovial aspiration for PJI workup was dominated by culture and cell count — tests with meaningful limitations. Culture is slow, affected by prior antibiotics, and now confirmed to have sensitivity of only 0.62.
When you aspirate a painful THA or TKA, alpha-defensin gives you the highest diagnostic accuracy of any single synovial biomarker. And critically, it is not affected by prior antibiotic administration. Pair it with leukocyte count, PMN%, LE, and synovial CRP to build a diagnostic battery.
Remember: even a test with 97% sensitivity and 96% specificity can have a PPV of 0.3 if your patient population has low PJI prevalence. Always interpret results in clinical context, not in isolation.