Related Experiment Video
Updated: Feb 24, 2026
Knee Arthrocentesis in Adults
Published on: February 25, 2022
The Leukocyte Esterase Strip Test has Practical Value for Diagnosing Periprosthetic Joint Infection After Total Knee
In J Koh1, Seung B Han2, Yong In3
1Department of Orthopaedic Surgery, St. Paul's Hospital, Seoul, Korea; Department of Orthopaedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Background:
Leukocyte esterase (LE) was recently reported to be an accurate marker for diagnosing periprosthetic joint infection (PJI) as defined by the Musculoskeletal Infection Society (MSIS) criteria. However, the diagnostic value of the LE test for PJI after total knee arthroplasty (TKA), the reliability of the subjective visual interpretation of the LE test, and the correlation between the LE test results and the current MSIS criteria remain unclear.
Methods:
This study prospectively enrolled 60 patients undergoing revision TKA for either PJI or aseptic failure. Serological marker, synovial fluid, and histological analyses were performed in all cases. The PJI group comprised 38 cases that met the MSIS criteria and the other 22 cases formed the aseptic group. All the LE tests were interpreted using both visual judgment and automated colorimetric reader.
Results:
When "++" results were considered to indicate a positive PJI, the sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy were 84, 100, 100, 79, and 90%, respectively. The visual interpretation agreed with the automated colorimetric reader in 90% of cases (Cronbach α = 0.894). The grade of the LE test was strongly correlated with the synovial white blood cell count (ρ = 0.695) and polymorphonuclear leukocyte percentage (ρ = 0.638) and moderately correlated with the serum C-reactive protein and erythrocyte sedimentation rate.
Conclusion:
The LE test has high diagnostic value for diagnosing PJI after TKA. Subjective visual interpretation of the LE test was reliable and valid for the current battery of PJI diagnostic tests according to the MSIS criteria.
Insights
The leukocyte esterase (LE) test is a reliable and accurate tool for diagnosing periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). Visual interpretation of the LE test is valid and correlates well with established diagnostic criteria.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Diagnostic Medicine
Background:
- Leukocyte esterase (LE) has emerged as a potential diagnostic marker for periprosthetic joint infection (PJI).
- The diagnostic utility of the LE test specifically for PJI following total knee arthroplasty (TKA) requires further clarification.
- Reliability of subjective LE test interpretation and its correlation with Musculoskeletal Infection Society (MSIS) criteria are not well-established.
Purpose of the Study:
- To evaluate the diagnostic value of the LE test for PJI in patients undergoing revision TKA.
- To assess the reliability of subjective visual interpretation of the LE test.
- To correlate LE test results with current MSIS criteria for PJI diagnosis.
Main Methods:
- Prospective enrollment of 60 patients undergoing revision TKA.
- Analysis of synovial fluid, serological markers, and histological data.
- LE testing performed with both visual judgment and automated colorimetric reader interpretation.
Main Results:
- LE test demonstrated high diagnostic accuracy (90%) with sensitivity of 84% and specificity of 100% when '++' indicated positive PJI.
- Visual interpretation showed 90% agreement with automated reader (Cronbach α = 0.894).
- LE test results strongly correlated with synovial white blood cell count and polymorphonuclear leukocyte percentage.
Conclusions:
- The LE test exhibits significant diagnostic value for identifying PJI after TKA.
- Subjective visual interpretation of the LE test is reliable and valid.
- The LE test supports current diagnostic protocols for PJI based on MSIS criteria.
