The positive percent agreement ranged from 66.0% (56.4C74.4) for EDI vs. low during the early stages of the disease but improved over time. After 14 days from symptom onset, Lionex and NovaTec showed the highest sensitivity at 87.9% (95% CI 72.7C95.2) and 86.4% (95% CI 78.5C91.7), respectively. The agreement with RT-PCR results based on Cohens kappa was as follows: Lionex (0.89) NovaTec (0.70) Dia.Pro (0.69) AnshLabs (0.63) EDI (0.55). Conclusion The Lionex and NovaLisa IgG ELISA kits, demonstrated the best overall performance. gene, Radequinil as described in (Corman et al., 2020). CT values 32 were considered positive. Characteristics of the 101 COVID-19 patients, including the demographic data and classification, are summarized in Table 1 . The patients had a median age (IQR) of 48.0 years (40.0C57.0), of which 89.1% were male and 4.9% were female. Patients in the three time points (7, 8C14 and 14 days) had a median age of 50.0 (39.3C56.8), 49.0 (41.3C58.5) and 46.0 (34.3C55.5) years, Radequinil respectively. Table 1 Demographic data and clinical characteristics of COVID-19 patients and control group. 0.05; (**) = 0.01; (***) = 0.001. Further details about the statistical analysis and calculations can be found in Table S4. Results Diagnostic assessment of the IgG ELISA kits according to the time of sample collection after symptom onset (n = 101) The diagnostic assessment of all ELISA kits according to each time-point after symptom onset (7 days, 8C14 days and 14 days) is usually summarized in Table 2 , Physique 1 and Physique 2 . Table 2 The diagnostic assessment of the different commercial IgG ELISA kits according to time of sample collection after symptoms onset. 0.05. In the first week of symptom onset (7 days), the sensitivity (95% CI) ranged from 57.1% (39.1C73.5) to 78.6% (60.5C89.8) for EDI and AnshLabs, respectively. The highest positive and negative predictive values were estimated at 95.0% (76.4C99.1) for Lionex and Radequinil 89.8% (79.5C95.3) for AnshLabs, respectively. The best Tmem9 agreement with RT-PCR was observed in Lionex, with 89.8% (82.2C94.4) positive percent agreement and Cohens kappa index of 0.73 (0.63C0.82). Radequinil The lowest agreement was observed in AnshLabs, with 76.5% (67.2C83.8) positive percent agreement and a kappa index of 0.49 (0.36C0.61). In the second week of symptom onset (8C14 days), all parameters increased compared with the first week, where the highest sensitivity was scored by AnshLabs at 90.0% (77.0C96.0). The highest positive and negative predictive values were estimated at 97.1% (85.1C99.5) for Lionex and 93.0% (83.3C97.2) for AnshLabs, respectively. The lowest agreement with RT-PCR was observed in AnshLabs, with 80.9% (72.6C87.2) positive percent agreement and a kappa index of 0.61 (0.51C0.72), while the highest agreement was scored by Lionex, with 92.7% (86.3C96.3) positive percent agreement and a kappa index of 0.84 (0.77C0.91). The performance of the evaluated IgG ELISA kits varied after 14 days of symptom onset. Compared with the second week, the sensitivity decreased in EDI, AnshLabs and Dia.Pro down to 60.6% (43.7C75.3), 84.8 (69.1C93.4) and 66.7% (49.6C80.3), respectively (Physique 2). However, the sensitivity slightly increased for NovaTec and Lionex, where both assays showed the highest sensitivity at 87.9% (72.7C95.2). Also, Lionex showed the highest positive and negative predictive values at 96.7% (83.3C99.4) and 94.5% (86.7C97.9), respectively. The positive percent agreement of EDI, AnshLabs and Dia.Pro also slightly dropped to 85.4% (77.4C91.0), 78.6% (69.8C85.5) and 87.4% (79.6C92.5), respectively. Whilst no change was observed in the positive percent agreement of NovaTec, it slightly increased in Lionex to 95.1% (89.1C97.9) with a Kappa index of 0.89 (0.82C0.95). Assay specificity according to the unfavorable Radequinil control subgroups (n = 70) All assays showed acceptable overall specificity, ranging from 85.7 to 98.6%, except Anshlabs, which had a 75.7% (53/70; 64.5C84.2) specificity. Lionex showed the highest specificity at 98.6% (69/70; 92.3C99.8), followed.