The Accuracy of Leukocyte Esterase and Glucose Levels in Synovial Fluid for Diagnosis of Acute Septic Arthritis: A Preliminary Report
Nopporn Vanaprasert MD1, Patarawan Woratanarat MD, PhD1, Parawee Chevaisrakul MD, PhD2, Mongkol Kunakorn MD3
Affiliation : 1 Department of Orthopaedics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand 2 Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand 3 Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Objective : To evaluate the diagnostic performance of synovial leukocyte esterase and glucose in differentiating between acute
bacterial arthritis and inflammatory arthritis.
Materials and Methods : A cross-sectional study was conducted from November 2015 to August 2016. Patients older than
18 years who had painful or swollen joints and who were suspected of having joint infection were enrolled. Synovial fluid
aspirated from the affected joint was centrifuged to precipitate RBC and clear supernatant was obtained. Leukocyte esterase
and glucose were identified using a standard colorimetric urine strip test which was graded as negative, 1+, 2+ or 3+.
Statistical analysis was done using STATA 13.0.
Results : There were 21 patients suspected of having septic arthritis. The average age was 68.5+14.5 years, and 52.4% were
female. The incidence of septic arthritis was 33.3%. Leukocyte esterase has a diagnostic sensitivity of 100% and a specificity
of 64.3%. The synovial glucose test has a sensitivity of 71.4% and a specificity of 71.4%. A combination of positive (2+ or
3+) leukocyte esterase and negative synovial glucose yielded a sensitivity of 71.4%, specificity of 92.9%, likelihood ratio
[LR] of a positive test of 10.0, LR of a negative test 0.31, and area under receiver operative characteristic [ROC] curve 0.82.
Conclusion : Combined synovial leukocyte esterase and glucose can be a useful diagnostic test for septic arthritis.
Keywords : Leukocyte esterase, Glucose, Septic arthritis, Diagnosis, Accuracy
