2025 Volume 74 Issue 2 Pages 268-276
The performance of five SARS-CoV-2 genetic analysers cobas® z480, Smart Gene®, ID NOWTM instrument, cobas® Liat® system and GeneXpert® system was evaluated respectively. The minimum detection sensitivity of each method was 1.0 copies/μL, 2.27 copies/μL, 5.75 copies/μL, 0.125 copies/μL and 2.0 copies/μL, respectively. 313 patients with SARS-CoV-2 infection or suspected infection were included in the study. The sensitivity, specificity and concordance rate were compared between the SG and z480 methods: sensitivity 93.2%, specificity 96.6% and concordance rate 94.7%; between the SG and ID NOW methods: sensitivity 91.7%, specificity 98.4% and concordance rate 95.1%; between the Liat and z480 methods: sensitivity 100.0%, specificity 82.4% and concordance rate 95.1%. The comparison between the GX and Liat methods showed a high correlation with a sensitivity of 100.0%, specificity of 93.8% and concordance rate of 96.7%. In the discordant cases, 14 of the 17 cases tended to have a high mean Ct value of 37.7, 9–59 days after onset of illness, and it was considered that a decrease in the amount of virus in the upper respiratory tract, differences in the detection sensitivity of the instruments and uneven distribution of virus during sampling affected the discrepancy in the results. The operation of tests including post-corona should be established after understanding the characteristics of the instruments and discussing the results with the clinical staff.
