Bedside Leukocyte Esterase Testing to aid in Diagnosing Bacterial Conjunctivitis in Children

Background: Conjunctivitis is a frequent symptom in pediatric emergency departments; however, the etiology of conjunctivitis is difficult to clinically differentiate. Objective: Our study objective was to evaluate the test performance characteristics of leukocyte esterase (LE) test strips in diagnosing bacterial conjunctivitis. Methods: Patients aged from 3 months through 21 years presenting to an emergency department with symptoms of conjunctivitis were prospectively enrolled from September 2018 to March 2020. A swab of the affected eye was applied to the LE test strip and another swab was sent for culture processing. The primary outcome was the association between LE test results and eye culture results. Results: We enrolled 189 patients. Overall, 117 eye cultures (62%) were positive. The sensitivity and specificity of LE testing was 96% (95% CI 90–98%) and 14% (95% CI 7–25%), respectively. Positive predictive value was 64% (95% CI 57–71%) and negative predictive value was 67% (95% CI 39–87%). Conclusions: The LE test strip had limited ability to differentiate bacterial conjunctivitis from other etiologies.