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Leukocyte esterase reagent strips for the rapid diagnosis of periprosthetic joint infection
Nathan G Wetters1, Keith R Berend, Adolph V Lombardi
1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois 60612, USA.
Abstract:
A total of 223 consecutive total hip or total knee arthroplasties were evaluated for periprosthetic joint infection (PJI) using leukocyte esterase reagent (LER) strips. Fifty-two LER strips were read as positive (23.3%), 106 were read as negative (47.5%), and 65 strips (29.2%) were unable to be read secondary to debris or blood in the aspiration. Using a synovial fluid white blood cell count of greater than 3000 white blood cell per microliter as an indicator of PJI, the sensitivity and specificity were 92.9% and 88.8%, respectively. When using positive cultures for diagnosis of PJI, sensitivity and specificity were 93.3% and 77.0% and 100% and 86.8% for the cases where a reoperation was performed and a combination of factors were used to define PJI. Leukocyte esterase reagent strips represent a rapid, inexpensive, and sensitive tool for the diagnosis of PJI. Their utility is limited, however, by blood or debris in the synovial fluid rendering them unreadable in one-third of cases.
Insights
Leukocyte esterase reagent (LER) strips offer a rapid, sensitive, and cost-effective method for diagnosing periprosthetic joint infection (PJI). However, their accuracy can be limited by synovial fluid contamination, impacting diagnostic reliability.
Area of Science:
- Orthopedics
- Infectious Diseases
- Medical Diagnostics
Background:
- Periprosthetic joint infection (PJI) is a serious complication following arthroplasty.
- Accurate and timely diagnosis of PJI is crucial for effective treatment and patient outcomes.
- Current diagnostic methods have limitations in sensitivity, specificity, or speed.
Purpose of the Study:
- To evaluate the diagnostic performance of leukocyte esterase reagent (LER) strips for identifying PJI.
- To compare LER strip results with established PJI diagnostic criteria, including synovial fluid white blood cell (WBC) counts and cultures.
- To assess the limitations of LER strips in clinical practice.
Main Methods:
- A prospective study evaluated 223 total hip or knee arthroplasties for PJI.
- Leukocyte esterase reagent (LER) strips were used to analyze synovial fluid.
- Results were compared against synovial fluid WBC counts (>3000 cells/µL) and microbiological cultures.
- Diagnostic sensitivity and specificity were calculated for LER strips.
Main Results:
- LER strips were positive in 23.3% and negative in 47.5% of cases.
- A significant proportion (29.2%) of LER strips were unreadable due to blood or debris.
- When compared to synovial fluid WBC counts, LER strips showed a sensitivity of 92.9% and specificity of 88.8%.
- Sensitivity and specificity were 93.3% and 77.0% when using positive cultures, and 100% and 86.8% for reoperation cases or combined PJI factors.
Conclusions:
- Leukocyte esterase reagent (LER) strips are a rapid, inexpensive, and sensitive tool for PJI diagnosis.
- The presence of blood or debris in synovial fluid can render LER strips unreadable, limiting their utility in approximately one-third of cases.
- LER strips can be a valuable adjunct to other diagnostic methods for PJI, particularly in settings where rapid results are needed.
