Evaluation of SARS-CoV-2 antigen detection kit via silver amplification immunochromatography: Comparative study with clinical laboratory immunoassay systems

• Published in: Japanese Journal of Medical Technology Vol. 74; no. 1; pp. 103 - 108
• Main Authors: OGAWA, Mizuki, NIWA, Ayumi, ICHIOKA, Rina, YOKOYAMA, Sodai, ISHIDA, Hidekazu, YONETAMARI, Jun, KAIHARA, Hiromitu, KIKUCHI, Ryosuke
• Format: Journal Article
• Language: Japanese
• Published: Japanese Association of Medical Technologists 25.01.2025; 一般社団法人 日本臨床衛生検査技師会
• Subjects: coronavirus disease 2019 (COVID-19); SARS-CoV-2 antigen detection kit; SARS-CoV-2抗原検出キット; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); silver amplification immunochromatography; 新型コロナウイルス感染症（COVID-19）; 重症急性呼吸器症候群コロナウイルス-2（SARS-CoV-2）; 銀増幅イムノクロマトグラフィ法
• ISSN: 0915-8669; 2188-5346
• DOI: 10.14932/jamt.24-53

The SARS-CoV-2 antigen test is a cost-effective and rapid method for detecting COVID-19. However, certain testing kits carry a significant risk of false negatives, necessitating careful result interpretation. This study evaluates the performance of an SARS-CoV-2 detection kit that employs silver amplification immunochromatography (SAIC). Sixty-one nasopharyngeal swab specimens, submitted to the laboratory in our hospital for genetic testing, were analyzed using the Fujifilm Dry-Chem IMMUNO AG Cartridge COVID-19 Ag. Results were compared against those from real-time PCR (Xpert Xpress SARS-CoV-2) and chemiluminescent enzyme immunoassay (CLEIA) (HISCL SARS-CoV-2 Ag). The concordance rate between the SAIC method and PCR for nucleic acid detection was 75.4%, with a sensitivity of 70.6% and a specificity of 100.0%, showing results almost equivalent to the CLEIA method. Notably, all specimens with a PCR Ct value of 27 or below were consistently detected as positive by the SAIC method. Additionally, the SAIC method could detect specimens with a Ct value up to 28.9 when compared to diluted specimen sensitivity. The findings suggest that the SAIC method has a sensitivity comparable to the CLEIA method, indicating its potential for high-sensitivity SARS-CoV-2 detection. The advantages of the SAIC method are that it does not require water or consumables and the device is compact, making it suitable for routine point-of-care testing (POCT). Furthermore, it holds promise for use in disaster scenarios or in settings with limited infrastructure, providing an efficient screening tool under such conditions.