The Utility of Leukocyte Esterase Strip Test in the Diagnosis of Pediatric Septic Arthritis.

BACKGROUND

Most tests used to diagnose pediatric septic arthritis are either not accurate or do not produce rapid results. A leukocyte esterase (LE) strip test has previously been validated for the diagnosis of adult native and periprosthetic joint infections. The purpose of this prospective study was to: (1) evaluate the performance characteristics of the LE strip test in the diagnosis of pediatric septic arthritis and (2) determine the false positive rate of LE strip test on the aseptic synovial fluid (SF).

METHODS

Between May 2016 and November 2018, SF was obtained from children who were hospitalized at our tertiary referral center on the basis of suspicion of septic arthritis. All patients underwent arthrocentesis, and the aspirate was tested with LE strip test, leukocyte count, and culture. Twenty-five patients satisfied the inclusion criteria. For the second part of the study, SF from 25 children undergoing surgery for developmental dysplasia of the hip was collected and tested with LE strip test, leukocyte count, and culture.

RESULTS

In the first part of this study, 19 joints were classified as septic and 6 as aseptic. Considering a positive LE strip test ("++" and "+++" readings) indicative of septic arthritis yielded a sensitivity of 100%, specificity of 83%, positive predictive value of 95%, and negative predictive value of 100%. In the second part, all 25 patients with an aseptic SF had a negative test result ("-" and "+" readings).

CONCLUSIONS

The LE strip test seems to be a valuable additional tool in the diagnosis of pediatric septic arthritis. The LE strip test has the advantages of being inexpensive and simple, providing real-time results and having a perfect negative predictive value to rule out the diagnosis of septic arthritis.

LEVEL OF EVIDENCE: Level II-diagnostic.