TABLE 6.

Identification of factors contributing to assay performance, antibody levels^a

Neutralization SARS-CoV-2 serological assay specificity and sensitivity by antibody levels
	Specificity (%)		Sensitivity (%)																Cohen's kappa agreement
Assay ID	N	Overall	N	Infected (low)	N	Infected (mid)	N	Infected (high)	N	Infected (variant)	N	Vaccinated (low)	N	Vaccinated (mid)	N	Vaccinated (high)	N	Overall	Overall
25	90	42.2	36	100.0	36	97.2	36	100.0	15	100.0	48	93.8	45	100.0	45	100.0	261	98.5	0.47
26	180	51.1	72	98.6	72	98.6	72	100.0	30	100.0	96	91.7	90	97.8	90	100.0	522	97.7	0.56
27	182	97.2	70	74.1	70	91.6	62	100.0	30	82.8	96	17.8	91	67.5	83	99.3	502	69.5	0.52
28	60	100.0	36	94.4	36	100.0	36	100.0	15	100.0	38	42.4	44	93.3	45	100.0	250	88.1	0.71
29	90	100.0	36	38.9	36	86.1	36	100.0	15	66.7	48	2.1	45	53.3	45	100.0	261	61.7	0.45
30	89	89.9	35	88.6	35	100.0	35	100.0	15	100.0	48	33.3	44	86.3	45	100.0	257	92.9	0.65
31	180	100.0	72	90.3	72	100.0	72	100.0	30	93.3	96	19.8	90	98.9	90	100.0	522	83.3	0.72
32	180	100.0	72	63.9	72	94.4	72	100.0	30	66.7	96	34.4	90	100.0	90	100.0	522	80.3	0.68
33	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–

^aFDA recommended performance thresholds (Pan Ig and IgG): Specificity ≥93%; Sensitivity ≥90%. Data highlighted in bold if below FDA recommended performance thresholds. Sensitivity and specificity analysis were not evaluated for Assay ID 33 due to no reported cutoff value for the assay, and dashes were added to indicate the data was not analyzed. Data analysis was performed prior to harmonization.