Table 3.

Agreements and correlation of SARS-CoV-2 antibody titer in positive samples between Abbott RBD, DiaSorin Trimeric S, Roche Elecsys and GenScript cPass assays.

Assay pair	Cohen's k	Spearman's rho (95% CI)	Passing-Bablok average difference (95%CI)
RBD/Trimeric S	0.93 (95% CI 0.88, 0.99)€	0.97 (95%CI 0.96, 0.98)*	−74.95 (−10,101.94, −9952.04)⁎⁎
RBD/Elecsys	0.92 (95% CI 0.87, 0.98)€	0.87 (95%CI 0.81, 0.92)*	−2280.84 (−13,052.84, −8491.16)⁎⁎
RBD/cPass	0.86 (95% CI 0.78, 0.93)€	0.94 (95%CI 0.90, 0.96)*	573.27 (−12,507.97, −13,654.50)⁎⁎
Trimeric S/Elecsys	0.88 (95% CI 0.81, 0.95)€	0.90 (95%CI 0.86, 0.93)*	−2205.89 (−11,716.78, −7304.99)⁎⁎
Trimeric S/cPass	0.88 (95% CI 0.81, 0.95)€	0.94 (95%CI 0.91, 0.96)*	650.93 (−2231.08, −3532.94)⁎⁎
Elecsys/cPass	0.78 (95% CI 0.69, 0.87 s)§	0.90 (95%CI 0.84, 0.93)*	3113.32 (−8083.30, −14,309.94)⁎⁎

^⁎Correlation is significant at p < 0.01.

^⁎⁎Average differences are significant at p < 0.05. Differences are measured in BAU/mL.

^§Cohen's kappa score of 0.7–0.8 was defined as good.

^€above 0.8 as excellent agreement.