Clinical Application and Quality Control Points of Light-Initiated Chemiluminescence Antigen Detection Kits in COVID-19 Prevention and Control

Clinical Applicable Scenarios and Sample Collection Specifications

The 2019-nCoV Antigen Detection Kit (Light-Initiated Chemiluminescence Assay) is primarily intended for symptomatic patients, screening of key populations, and emergency testing scenarios. Since this method requires a dedicated light-initiated chemiluminescence analyzer, it is mostly used in fever clinics, emergency clinical laboratories, or central laboratories with appropriate conditions. Samples are generally collected using nasal swabs or oropharyngeal swabs and must be immediately placed into the viral preservation solution provided by the manufacturer after collection. The composition of the preservation solution may affect antigen stability; samples should be temporarily stored at 2–8°C as required by the instructions and tested within the specified time frame. It is worth noting that hemoglobin, mucus, or excessively high salt concentrations in samples may interfere with the light-initiated signal, and severely hemolyzed or viscous samples should be recollected.

Quality Control and Performance Verification

Before using this kit, laboratories should establish an internal quality control program in accordance with ISO 15189 or the quality management requirements of medical institutions. Generally, at least one negative control and one positive control (manufacturer's quality control materials or third-party quality control materials) should be run during daily testing to monitor inter-batch differences in reagents and instrument status. The light-initiated chemiluminescence assay is temperature-sensitive; the testing environment temperature should ideally be maintained at 15–30°C to avoid changes in luminescence efficiency caused by instrument overheating or overcooling. When quality control results fall outside the preset range, testing should be stopped and the cause investigated (e.g., reagent failure, contamination of the instrument's optical pathway), and verification should be repeated after calibration or replacement. Regular participation in external quality assessment programs organized by national or provincial clinical testing centers is also an important means of ensuring result accuracy.

Interpretation of Results and Limitations

The test results of this kit should be comprehensively judged in combination with epidemiological history, clinical manifestations, and other laboratory tests. The light-initiated chemiluminescence assay detects viral nucleocapsid protein or spike protein fragments. A positive result indicates the presence of viral antigen in the sample, but false negatives may occur in individuals in the early stage of infection, with recurrent positivity, or with extremely low viral loads. In addition, reagents from different manufacturers target different antigenic epitopes and have different cut-off values, so numerical values should not be compared across reagents. According to current Chinese regulations, antigen testing cannot be used alone as a basis for confirmed diagnosis; nucleic acid testing remains the gold standard. Kit instructions typically explicitly state that the product is "for in vitro diagnostic use only, intended for use by professionals, and not to be used as the sole basis for diagnosis."

Registration Compliance and Ongoing Supervision

The 2019-nCoV Antigen Detection Kit (Light-Initiated Chemiluminescence Assay) marketed in China must obtain an NMPA medical device registration certificate. Users should verify product registration information through the official website of the National Medical Products Administration and monitor subsequent changes (e.g., applicable sample types, performance updates). Bioreagent and medical device companies must strictly comply with the Regulations on the Supervision and Administration of Medical Devices and the Measures for the Registration and Filing Administration of In Vitro Diagnostic Reagents, and must not use expressions such as "" or "completely replace nucleic acid testing" in promotional materials. Medical institutions should obtain complete technical reports and clinical evaluation data when procuring products to ensure that product performance meets the intended use.