Table 3.

Comparison of plasma and serum based anti-SARS-CoV-2 antibody detection.

		Epitope		Euroimmun		Roche
		Plasma	Serum	Plasma	Serum	Plasma	Serum
Absolute result	Mean	0.90	0.90	4.00	4.40	14.00	7.50
	Range	−0.01–1.48	−0.023–1.48	0.35–8.63	0.35–9.69	0.08–56.7	0.08–42.7
	Median	1.30	1.40	2.60	4.50	8.40	1.40
	Kendalĺs tau	0.82		0.77		0.60
	Mean bias (95% CI)	−11.65% (-36.13% − 12.83%)		23.12% (-8.61% − 54.85%)		−28.57% (-45.18% - −11.96%)
Interpreted result	Overall Agreement (%)	100.00		90.0*/95.0#		100.00
	Positive Agreement (%)	100.00		92.3*/100#		100.00
	Negative Agreement (%)	100.00		85.7*/87.5#		100.00
	Coheńs kappa	1.00		0.78 (0.49–1.07)*/0.89 (0.69–1.10)#		1.00