Characteristics of Three Different Chemiluminescence Assays for Testing for SARS-CoV-2 Antibodies

Table 1

Multilevel likelihood ratios as well as sensitivity and specificity are given for the different tests at different cut-off levels (manufacturers’ cut-offs and half and double the manufacturers’ cut-offs) for ruling in or ruling out a COVID-19 diagnosis. +LR, positive likelihood ratio; -LR, negative likelihood ratio. CMIA, chemiluminescence microparticle immunoassay; LIA, luminescence immunoassay; ECLIA, electrochemiluminescence immunoassay; Sens, sensitivity; Spec, specificity; CI, confidence interval.

	+LR at cut-off/2	-LR at cut-off/2	+LR at cut-off	-LR at cut-off	+LR at 2x cut-off	-LR at 2x cut-off
	(Spec, [95% CI])	(Sens, [95% CI])	(Spec, [95% CI])	(Sens, [95% CI])	(Spec, 95% CI)	(Sens, 95% CI)
CMIA	60	0.043	374	0.056	485	0.18
	(98.4 [97.5,99.0])	(95.8 [91.0-98.4])	(99.8 [99.3,99.9])	(94.4 [89.2,97.5])	(99.8 [99.4,100])	(81.7 [74.3,87.7])
LIA	82	0.035	351	0.12	1027	0.14
	(98.8 [98.0,99.4])	(96.5 [92.1,98.9])	(99.8 [99.3 - 99.9])	(88,2 [81.8,93.0])	(100 [99.7,100])	(86.1 [79.4 - 91.3])
ECLIA	575	0.035	958	0.042	>958	0.042
	(99.8 [99.4,100])	(96.5 [92.1,98.9])	(99.9 [99.5,100])	(95.8 [91.2,98.5])	(100 [99.7,100])	(95.8 [91.2,98.5])