Table 1.

Ability of serological assays to qualitatively identify presence of neutralizing antibodies.

	Cut off	TP	FN	TN	FP	n	%SENS	%SPEC	%PPV	%NPV
Abbott N (NC IgG)	≥1.4	307	43	42	29	421	88	59	91	49
	≥4.5	166	184	66	5	421	47	93	97	26
Diasorin S1/2 (S1/2 IgG)	≥15	331	15	34	37	417	96	48	90	69
Siemens COV2T (RBD total)	≥1	346	4	9	62	421	99	13	85	69
	≥4.8	311	39	36	35	421	89	51	90	48
Roche N (NC total)	≥1	346	4	2	69	421	99	3	83	33
Roche S (RBD total)	≥0.8	350	0	2	69	421	100	3	84	100
	≥132	188	162	63	8	421	54	89	96	28
Euroimmun (S1 IgG)	≥1.1	315	33	51	20	419	91	72	94	61
	≥3.5	193	155	69	2	419	55	97	99	31
Diasorin Trimeric S (S stabilised native IgG)	≥ 13	340	9	18	53	420	97	25	87	67
Abbott IgGII IgG (RBD IgG)	≥50	347	0	3	68	418	100	4	84	100
	≥500	226	121	67	4	418	65	94	98	36
Siemens sCOVG (RBD IgG)	≥1	328	21	36	35	420	94	51	90	63
	≥4.8	217	132	71	0	420	62	100	100	35
cPASS (sVNT50)	≥2	88	0	0	28	116	100	0	76
	≥10	69	19	26	2	116	78	93	97	58
NT50 relative to wt	≥50	350	0	71	0	421	100	100	100	100

TP, true positives are samples that score positive in each assay and have NT50 >50 (the limit of detection in the neutralization assay). FN, false negatives score negative in serological assays but have NT50>50. TN, true negatives score negative in serological assays and have NT50<50. FP, false positives score positive in serological assays but have NT50<50. %SENS, sensitivity measured as the ration of TP over samples with NT50>50. %SPEC, specificity measured as the ratio of TN over samples that with NT50<50. %PPV, positive predictive value is the ratio of TP over total positive serological assay results. %NPV, negative predictive valus is the ratio of TN over total negative serological assay results.

Top row is manufacturer recommended cut off, bottom FDA recommended cut off when available.