Results
In total, 1,971 patients underwent RT-PCR assays for SARS-CoV-2 in the emergency department during the study period (Table I). The patients included 1,082 female patients (54.9%) and 889 male patients (45.4%). The median age of all patients was 61 years (0–100 years). KTAS levels were distributed as follows: KTAS 1: 4 (0.2%), KTAS 2: 177 (9.0%), KTAS 3: 899 (45.6%), KTAS 4: 254 (12.9%), and KTAS 5: 637 (32.3%). COVID-19-associated symptoms were observed in 547 patients (27.8%).
The results of the STANDARD M10 and Allplex assays are shown in Table II. A total of 123 specimens were positive using the Allplex and 122 specimens were positive using STANDARD M10. Overall agreement with the STANDARD M10 and Allplex assays was 99.5% (95% confidence interval CI: 99.1–99.8%), and the kappa value was 0.96 (95% CI: 0.94­–0.99). PPA and NPA values of STANDARD M10 were 95.9% (95% CI: 90.8–98.3%) and 99.8% (95% CI: 99.4–99.9%), respectively, based on the Allplex.
Ct values of positive or inconclusive results from the two RT-PCR assays are described in Table III. Ct values of the E gene andRdRP (orf1ab ) of concordant positive results were higher for Allplex than for STANDARD M10 (P < 0.001 for both). Two specimens, which were positive with Allplex and negative with STANDARD M10, showed median Ct values of 36.75, 37.96, and 36.50 for theE , RdRP , and N genes, respectively. Three positive specimens with Allplex and inconclusive with STANDARD M10 showed median Ct values of 35.75, 37.33, and 36.85 for the E , RdRP , andN genes, respectively. Ct of orf1ab was not detected with STANDARD M10 for these three specimens. The Ct value of inconclusive results of Allplex, which were positive or negative with STANDARD M10, was higher than 38.0. The four specimens which were positive with STANDARD M10 showed median Ct values of 35.15 and 34.59 for the Egene and orf1ab , respectively. Nine specimens of STANDARD M10 were inconclusive, and those negative with Allplex showed Ct values of 35.29 and 34.98 for the E gene and orf1ab , respectively. No specimens were negative with Allplex and positive with STANDARD M10.