Test groups (true negatives/non‐COVID cases) Specificity (95% CI)
	IgG	IgM	IgG or IgM	Total Ab	IgA	IgA or IgG
Overall result	96 (6036/6176)	44 (2492/2625)	36 (2047/2175)	22 (1407/1411)	5 (278/311)	2 (203/219)
	98.6 (98.0, 99.0)	97.0 (95.1, 98.2)	96.8 (94.4, 98.2)	99.8 (98.6, 100)	89.1 (80.6, 94.2)	92.7 (88.4, 95.5)
By test method
ELISA	28 (1573/1619)	8 (495/503)	3 (261/270)	3 (158/158)	5 (278/311)	2 (203/219)
	98.0 (96.5, 98.8)	98.8 (96.6, 99.6)	96.9 (85.4, 99.4)	100a (97.7, 100)**	89.1 (80.6, 94.2)	92.7 (88.4, 95.5)
CLIA	34 (2465/2514)	4 (202/204)	1 (20/20)	16 (1249/1253)
	98.9 (98.1, 99.4)	99.4 (96.2, 99.9)	100a (83.2, 100)**	99.8 (98.5, 100)
Lateral flow/CGIA/FIA	34 (1998/2043)	32 (1795/1918)	31 (1707/1826)
	98.6 (97.6, 99.2)	95.4 (92.8, 97.0)	96.4 (93.7, 98.0)
COMPARISON	0.2587	0.0097	0.4655
By antigen
N‐based	29 (1889/1916)	11 (540/559)	6 (389/397)	12 (786/787)
	99.1 (98.3, 99.5)	97.5 (93.9, 99.0)	99.0 (95.1, 99.8)	99.7 (98.2, 99.9)
S‐based	38 (2668/2738)	8 (719/746)	10 (652/671)	10 (656/657)	5 (278/311)	2 (203/219)
	98.3 (97.3, 99.0)	97.5 (93.0, 99.1)	99.0 (96.2, 99.7)	99.8 (98.3, 100)	89.1 (80.6, 94.2)	92.7 (88.4, 95.5)
N‐ and S‐based	17 (877/895)	15 (718/755)	10 (500/542)
	98.9 (97.4, 99.5)	97.7 (94.5, 99.1)	95.9 (88.5, 98.6)
Unclear/not reported	12 (602/627)	10 (515/565)	10 (506/565)
	96.9 (94.0, 98.4)	94.0 (87.2, 97.3)	90.9 (85.6, 94.4)
	0.2515	0.9853	0.1613	0.6053
aP value obtained using ‘meqrlogit’; P < 0.0001 (comparison excluded ‘other/mixed/unclear’ group) *95% exact binomial confidence interval **97.5% one‐sided exact binomial confidence interval CI: confidence interval CGIA: colloidal gold immunoassayCLIA: chemiluminescent immunoassayELISA: enzyme‐linked immunoassayFIA: fluorescence immunoassay