Multicenter evaluation of two chemiluminescence and three lateral flow immunoassays for the diagnosis of COVID-19 and assessment of antibody dynamic responses to SARS-CoV-2 in Taiwan

Figures & data

Table 1. Information on the two chemiluminescence immunoassays used for the diagnosis of coronavirus disease (COVID-19).

Parameter	Roche Elecsys® Anti-SARS-CoV-2	Abbott SARS-CoV-2 IgG
Company (city, country)	Roche Diagnostics (Basel, Switzerland)	Abbott Laboratories (IL, USA)
Targeting antibody	All antibodies (including IgG)	IgG
Immunoassay	Electrochemiluminescence	Chemiluminescent microparticle
Analyzer	Cobas e analyzers (e 411, e 601, and e 602)	ARCHITECT i System (i2000SR and i1000SR)
Qualitative analysis	Yes	Yes
Protein targeting	Nucleocapsid	Nucleocapsid
Specimen type(s)	Serum or plasma	Serum or plasma
Specimen amount required	20 µL (cobas e 411/cobas e 601/cobas e 602 modules) 10 µL (cobas e 601)	25 µL
Result interpretation	Cutoff index, COI <1.0: non-reactive (negative); ≥1.0: reactive (positive)	Index [Sample/Calibrator], S/C <1.4: negative; ≥1.4: positive
Testing time	18 min	15 min
Reported sensitivity or positive percent agreement (PPA) (95% CI) based on qRT-PCR results	204 serum samples from 69 symptomatic patients Days post PCR confirmation (sensitivity): 0–6 days (n = 116), 65.5% (56.1–74.1%) 7–13 days (n = 59), 88.1% (77.1–95.1%) ≥14 days (n = 29), 100% (88.1–100%)	122 serum samples from 31 patients Days post-symptom onset (PPA) <3 days (n = 4), 0.0% (0.0–60.2%) 3–7 days (n = 8), 25.0% (3.2–65.1%) 8–13 days (n = 22), 86.4% (65.1–97.1%) ≥14 days (n = 88), 100% (95.9–100.0%)
Reported specificity or negative percent agreement (NPA), (95% CI)	5272 samples (from routine diagnostic tests, blood donor tests, a common cold panel, and a coronavirus panel) obtained before December 2019 (10 false positives were detected). Specificity: 99.8% (99.7–99.9%)	997 specimens collected prior to September 2019 (4 false positives were detected) NAP: 99.6% (99.9–99.9%) 73 specimens collected in 2020 from patients exhibiting signs of respiratory illness who tested negative for SARS-CoV-2 by the qRT-PCR method NPA: 100% (95.1–100.0%)
Confirmed cross-reactivity with antibodies against non-coronaviruses	NA	One of five patients showed positivity for CMV IgG
Cross-reactivity with antibody against other coronaviruses SARS and MERS Other seasonal coronaviruses	NA Yes (40 potentially cross-reactive samples from individuals with past infection with coronaviruses HKU1, NL63, 229E, or OC43, confirmed by PCR)	NA NA
Registration	CE-IVD, USFDA	CE-IVD, US FDA
Reference	[24]	[25]

CE-IVD, Conformité Européenne in vitro diagnostic device; CMV, cytomegalovirus; MERS, Middle East respiratory syndrome; NA, not available; qRT-PCR, real-time reverse transcriptase-polymerase chain reaction; SARS, severe acute respiratory syndrome; S/C, sample/control; US FDA, Food and Drug Administration of the United States.

COVID-19, coronavirus disease 2019; ICU, intensive care unit; ECMO, extracorporeal membrane oxygenation.

Table 2. Clinical characteristics of the 74 patients with confirmed COVID-19, stratified based on the availability of sequential samples for estimating the date of seroconversion.

Characteristics^a	All patients	Seroconversion assessable^b	Seroconversion not assessable^b	p
No. of patients/no. of serum samples	74/346	48/230	26/116
Age (years)	38.5 ± 16.2	37.8 ± 16.3	39.9 ± 16.2	0.600
Male sex	41 (55.4)	26 (54.2)	15 (57.7)	0.771
Comorbid medical condition
Diabetes mellitus	3 (4.1)	1(2.1)	2 (7.7)	0.281
Malignancy	2 (2.7)	0 (0)	2 (7.7)	0.120
Coronary artery disease	2 (2.7)	2 (4.2)	0 (0)	0.538
Congestive heart failure	1 (1.4)	1 (2.1)	0 (0)	1.000
Initial presentation
Fever	34 (45.9)	22 (45.8)	12 (46.2)	0.979
Headache	18 (24.3)	13 (27.1)	5 (19.2)	0.452
Myalgia	12 (16.2)	6 (12.5)	6 (23.1)	0.323
Malaise	19 (25.7)	11 (22.9)	8 (30.8)	0.460
Upper airway symptoms^c	46 (62.2)	29 (60.4)	17 (65.4)	0.674
Low respiratory tract symptoms^d	49 (66.2)	32 (66.7)	17 (65.4)	0.911
Diarrhea	21 (28.4)	14 (29.2)	7 (26.9)	0.838
Treatment outcome
Length of hospital stay (days)	28.5 ± 13.4	28.2 ± 12.6	29.0 ± 15.0	0.815
Diagnosis of pneumonia	28 (37.8)	20 (41.7)	8 (30.8)	0.356
ICU admission	5 (6.8)	2 (4.2)	3 (11.5)	0.337
Ventilator required	5 (6.8)	2 (4.2)	3 (11.5)	0.337
ECMO support received	1 (1.4)	0 (0)	1 (3.8)	0.351
Hospital mortality	1 (1.4)	0 (0)	1 (3.8)	0.351
Sample collection
Available sample number	4.7 ± 4.6	4.8 ± 2.7	4.5 ± 7.1	0.773
No. of days between symptom onset and sample collection	11.4 ± 14.8	5.7 ± 4.0	22.0 ± 20.8	<0.001

^a All values are expressed as mean ± SD or number (percentage).

^b Patients for whom sequential samples adequate for judging the approximate date of seroconversion were available.

^c Includes rhinorrhea, nasal stiffness, sore throat, and hoarseness.

^d Includes cough, productive sputum, dyspnea, and chest pain.

Figure 1. Percentage of samples showing positive antibody findings when examined using the five studied serological tests after symptom onset.

Figure 2. Chemiluminescent signal values of the two chemiluminescence immunoassays for anti-SARS-CoV-2 antibodies detection after symptom onset. (A) Roche Elecsys® Anti-SARS-CoV-2 Assay. (B) Abbott SARS-CoV-2 IgG Assay.

Table 3. Agreement among findings from the five anti-SARS-CoV-2 antibody tests.

		Roche^a	Abbott^b	Wondfo^c	ASK^d			Dynamiker^e
					IgM	IgG	IgG/IgM	IgM	IgG	IgG/IgM
Roche^a		–	0.784	0.659	0.409	0.533	0.681	0.728	0.716	0.745
Abbott^b		–	–	0.683	0.428	0.617	0.657	0.757	0.759	0.789
Wondfo^c		–	–	–	0.570	0.611	0.830	0.621	0.609	0.635
ASK^d	IgM	–	–	–	–	0.334	0.632	0.436	0.400	0.411
	IgG	–	–	–	–	–	0.632	0.605	0.671	0.621
	IgG/IgM	–	–	–	–	–	–	0.627	0.630	0.642
Dynamiker^e	IgM	–	–	–	–	–	–	–	0.919	0.966
	IgG	–	–	–	–	–	–		–	0.952
	IgG/IgM	–	–	–	–	–	–			–

^a Roche Elecsys® Anti-SARS-CoV-2 assay.

^b Abbott SARS-CoV-2 IgG assay.

^c Wondfo SARS-CoV-2 Antibody Test.

^d ASK COVID-19 IgG/IgM Rapid Test.

^e Dynamiker 2019-nCoV IgG/IgM Rapid Test.

Table 4. Evaluation of cross-reactivity for the five anti-SARS-CoV-2 antibody tests.

Cohort	No. of specimens tested	No. of specimens with positive results
		Roche Elecsys® Anti-SARS-CoV-2 assay	Abbott SARS-CoV-2 IgG assay	Wondfo SARS-CoV-2 antibody test	ASK COVID-19 IgG/IgM rapid test	Dynamiker 2019-nCoV IgG/IgM rapid test
Total no. of specimens tested	194	2	4	0	0	0
For patients treated between January 31 and May 31, 2020
Patients with ARI and negative qRT-PCR results on ≥2 tests, without other confirmed etiologies for ARI	70	0	0	0	0	0
Patients with ARI and negative qRT-PCR results on ≥2 tests showing the presence of specific etiologies (respiratory tract [antigens] or serum [antibodies])	50	2	2	0	0	0
Coronavirus OC43	2	0	0	0	0	0
Coronavirus 229E	1	0	0	0	0
CMV IgG/IgM	7	1 (1.56)^a	0	0	0	0
CMV IgG/IgM and HSV-IgM	1	0	0	0	0	0
CMV IgG	11	1 (1.42)^a	1 (1.98)^a	0	0	0
CMV IgM and HSV-IgM	1	0	0	0	0	0
CMV IgM and HSV-IgM and EBV VCA-IgM	1	0	1 (1.61)^a	0	0	0
HSV-IgM	1	0	0	0	0	0
EBV VCA-IgM	5	0	0	0	0	0
Mycoplasma pneumoniae IgM	5	0	0	0	0	0
Chlamydophila trachomatis IgG	5	0	0	0	0	0
Respiratory syncytial virus (positive antigen test)	2	0	0	0	0	0
Influenza A virus (positive rapid antigen test)	4	0	0	0	0	0
Influenza B virus (positive rapid antigen test)	4	0	0	0	0	0
Patients showing the presence of any specific auto-antibodies^b in their sera (May 1 to May 31, 2020)	36	0	1 (2.17)^a,c	0	0	0
For patients treated between August 1 and December 31, 2019
Patients showing the presence of specific antigens/antibodies in their sera	38	0	1	0	0	0
Mycoplasma pneumoniae IgM	15	0	1 (4.54)^a,d	0	0	0
Chlamydophila pneumophilia IgM	5	0	0	0	0	0
EBV VCA-IgA	10	0	0	0	0	0
Respiratory syncytial virus (positive antigen test)	1	0	0	0	0	0
Influenza A virus (positive rapid antigen test)	3	0	0	0	0	0
Influenza B virus (positive rapid antigen test)	4	0	0	0	0	0

SARS-CoV-2, severe acute respiratory tract syndrome coronavirus 2; COVID-19, coronavirus disease 2019; ARI, acute respiratory tract infection; qRT-PCR, real-time reverse transcriptase-polymerase chain reaction; CMV, cytomegalovirus; HSV, herpes simplex virus; EBV, Epstein-Barr virus; VCA, viral capsid antigen.

^a The serum sample was additionally tested for the presence of rheumatoid factor, which showed a negative result (<10.1 IU/mL).

^b Includes anti-nuclear, anti-ENA, anti-SS-A, anti-RNP, anti-SCL-70, anti-CCP, anti-Jo-1, anti-B2 GP1, anti-cardiolipin IgM, anti-cardiolipin IgG, anti-CENP, anti-MPO (P-ANCA), and anti-ribosomal-P antibodies, anti-basement membrane zone antibodies, anti-intercellular substance antibodies, anti-mitochondrial antibodies, and anti-gastric parietal cell antibodies.

^c Serum was positive for anti-nuclear (1:1280 + homogeneous), anti-ribosomal-P (241.08), and anti-ds DNA (237.79 WHO units/mL) antibodies but negative for anti-CMV IgM and IgG.

^d Also positive for anti-CMV IgG antibodies (no anti-CMV IgM antibodies).

Figure 3. Parallel comparisons of the cumulative probability of seroconversion detection among the five studied serological tests.

Figure 4. Detection of seroconversion in patients with COVID-19 with or without pneumonia. (A) Presumptive seroconversion based on earliest detection by any serological test. (B) Roche Elecsys® Anti-SARS-CoV-2 Assay. (C) Abbott SARS-CoV-2 IgG Assay.

Figure 5. Comparison of chemiluminescent signal values in patients with COVID-19 with or without pneumonia. (A) Roche Elecsys® Anti-SARS-CoV-2 Assay. (B) Abbott SARS-CoV-2 IgG Assay.

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