Author(s)

Yuping Kang ¹, Shaojin Zhang ¹, Kechao Cheng ¹

Affiliation(s)

¹ School of Medical Technology and Engineering, Gansu Health Vocational College, Lanzhou, Gansu, 730207, China

Corresponding Author

Yuping Kang

ABSTRACT

This clinical validation study systematically evaluates the diagnostic performance of the S. pneumoniae and L. pneumophila Combo Rapid Test Cassette (ISLC-R125, Hangzhou AllTest Biotech Co., Ltd.), a qualitative in vitro diagnostic device for simultaneous detection of Streptococcus pneumoniae and Legionella pneumophila antigens from human urine specimens. A commercially available rapid antigen test kit targeting the two pathogens was adopted as the reference assay for side by side performance comparison. A total of 103 urine samples from patients with suspected pneumococcal infection and 105 urine samples from individuals with suspected legionellosis were enrolled in the clinical trial cohort. For S. pneumoniae antigen detection, the investigational cassette achieved a relative sensitivity of 90.0% (95% CI: 55.5%–99.7%), relative specificity of 98.9% (95% CI: 94.2%–>99.9%), and overall diagnostic accuracy of 98.1% (95% CI: 93.2%–99.8%). For L. pneumophila antigen detection, the assay yielded a relative sensitivity of 97.0% (95% CI: 84.2%–99.9%), relative specificity of 98.6% (95% CI: 92.5%–>99.9%), and overall diagnostic accuracy of 98.1% (95% CI: 93.3%–99.8%). All testing operations were performed within the validated storage and operating temperature range of 2-30°C. Test results were uniformly analyzed and interpreted by the LF Reader Plus instrument to eliminate subjective visual judgment of test lines; visual manual reading of test lines is prohibited per the official product instructions, with standardized positive, negative or invalid diagnostic results directly displayed on the instrument screen. All test cassettes are single-use disposable consumables. The multiplex combo assay exhibited high diagnostic concordance with the comparative reference rapid kit, with no notable cross-reactivity against a broad panel of common respiratory pathogens and minimal invalid test rates observed during analytical and clinical testing. This dual-target urinary antigen rapid test delivers rapid, objective point-of-care screening for community-acquired pneumonia caused by S. pneumoniae and L. pneumophila, supporting streamlined clinical laboratory and emergency department diagnostic workflows.

KEYWORDS

Streptococcus pneumoniae; Legionella pneumophila; Urinary antigen; Rapid chromatographic immunoassay; Point-of-care testing

CITE THIS PAPER

Yuping Kang, Shaojin Zhang, Kechao Cheng. Performance Evaluation of S. pneumoniae and L. pneumophila Combo Rapid Test Cassette (Urine, Ref.: ISLC-R125) via Clinical Validation. MEDS Clinical Medicine (2026). Vol. 7, No. 3, 15-21. DOI: http://dx.doi.org/10.23977/medsc.2026.070303.

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