Development and implementation of validation criteria for diagnostic test systems detecting SARS-CoV-2 markers during the COVID-19 pandemic in the Republic of Belarus

Objective. To develop and practically validate a system of interim quality assessment criteria for unregistered diagnostic test systems intended for the detection of SARS-CoV-2 antibodies and antigens, enabling the rapid selection of reliable products for clinical and epidemiological practice across the Republic of Belarus.
Materials and methods. The criteria were developed based on four principles: operational efficiency (shortening timelines by focusing on critical parameters), acceptable risk (balancing speed of deployment against potential harm from diagnostic errors), adaptability (flexibility depending on pathogen properties and epidemic phase), and stepwise validation (accelerated initial assessment followed by full registration). For antigen rapid tests, 50 nasopharyngeal swabs with known PCR results were used, stratified by viral load (Ct < 20, Ct = 20–30, Ct > 30). Statistical analysis included calculation of sensitivity and specificity, Clopper – Pearson exact method for binomial proportions, and kappa coefficient for agreement. All criteria were enacted by orders of the Ministry of Health of the Republic of Belarus. Over the pandemic period, 39 validation studies were conducted (6 for antibody detection and 33 for virus antigen detection).
Results. A positive conclusion was issued for 61.5 % of the evaluated systems. The proposed algorithm enabled the rapid selection of high-quality test systems and prevented the introduction of ineffective diagnostic products into clinical practice.
Conclusion. The developed validation system can serve as a model for rapid response in the event of epidemiological emergencies, allowing timely deployment of reliable diagnostic tools.

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