Table 2 Summary statistics for immunochromatographic LFAs and ELISAs^a

From: Evaluation of SARS-CoV-2 serology assays reveals a range of test performance

Percentage of positive specimens from patients who tested positive for SARS-CoV-2 by RT–PCR
	IgM				IgG				IgM or IgG
Assay	Total n	Positive	%	95% CI	Total n	Positive	%	95% CI	Total n	Positive	%	95% CI
*Immunochromatographic LFAs*
Biomedomics
1–5 d	27	7	25.9	11.1–46.3	27	6	22.2	8.6–42.3	27	8	29.6	13.8–50.2
6–10 d	36	22	61.1	43.5–76.9	36	19	52.8	35.5–69.6	36	23	63.9	46.2–79.2
11–15 d	33	25	75.8	57.7–88.9	33	23	69.7	51.3–84.4	33	26	78.8	61.1–91.0
16–20 d	19	16	84.2	60.4–96.6	19	14	73.7	48.8–90.9	19	17	89.5	66.9–98.7
>20 d	11	9	81.8	48.2–97.7	11	9	81.8	48.2–97.7	11	9	81.8	48.2–97.7
Bioperfectus
1–5 d	28	11	39.3	21.5–59.4	28	7	25.0	10.7–44.9	28	11	39.3	21.5–59.4
6–10 d	35	26	74.3	56.7–87.5	35	23	65.7	47.8–80.9	35	27	77.1	59.9–89.6
11–15 d	34	28	82.4	65.5–93.2	34	27	79.4	62.1–91.3	34	30	88.2	72.5–96.7
16–20 d	19	16	84.2	60.4–96.6	19	14	73.7	48.8–90.9	19	17	89.5	66.9–98.7
>20 d	10	10	100.0	69.2–100.0	10	9	90.0	55.5–99.7	10	10	100.0	69.2–100.0
DecomBio
1–5 d	26	8	30.8	14.3–51.8	26	7	26.9	11.6–47.8	26	8	30.8	14.3–51.8
6–10 d	36	24	66.7	49.0–81.4	36	24	66.7	49.0–81.4	36	24	66.7	49.0–81.4
11–15 d	33	29	87.9	71.8–96.6	33	29	87.9	71.8–96.6	33	29	87.9	71.8–96.6
16–20 d	18	14	77.8	52.4–93.6	18	14	77.8	52.4–93.6	18	14	77.8	52.4–93.6
>20 d	11	10	90.9	58.7–99.8	11	10	90.9	58.7–99.8	11	10	90.9	58.7–99.8
DeepBlue
1–5 d	28	12	42.9	24.5–62.8	28	6	21.4	8.3–41.0	28	12	42.9	24.5–62.8
6–10 d	36	28	77.8	60.8–89.9	36	18	50.0	32.9–67.1	36	28	77.8	60.8–89.9
11–15 d	34	28	82.4	65.5–93.2	34	21	61.8	43.6–77.8	34	28	82.4	65.5–93.2
16–20 d	19	16	84.2	60.4–96.6	19	15	78.9	54.4–93.9	19	17	89.5	66.9–98.7
>20 d	11	10	90.9	58.7–99.8	11	9	81.8	48.2–97.7	11	10	90.9	58.7–99.8
Innovita
1–5 d	27	4	14.8	4.2–33.7	27	7	25.9	11.1–46.3	27	7	25.9	11.1–46.3
6–10 d	36	12	33.3	18.6–51.0	36	17	47.2	30.4–64.5	36	20	55.6	38.1–72.1
11–15 d	31	12	38.7	21.8–57.8	32	25	78.1	60.0–90.7	32	25	78.1	60.0–90.7
16–20 d	13	4	30.8	9.1–61.4	13	9	69.2	38.6–90.9	13	9	69.2	38.6–90.9
>20 d	6	1	16.7	0.4–64.1	6	4	66.7	22.3–95.7	6	5	83.3	35.9–99.6
Premier
1–5 d	28	10	35.7	18.6–55.9	28	6	21.4	8.3–41.0	28	10	35.7	18.6–55.9
6–10 d	35	25	71.4	53.7–85.4	35	18	51.4	34.0–68.6	35	25	71.4	53.7–85.4
11–15 d	34	28	82.4	65.5–93.2	34	22	64.7	46.5–80.3	34	29	85.3	68.9–95.0
16–20 d	19	16	84.2	60.4–96.6	19	14	73.7	48.8–90.9	19	17	89.5	66.9–98.7
>20 d	11	10	90.9	58.7–99.8	11	9	81.8	48.2–97.7	11	10	90.9	58.7–99.8
Sure
1–5 d	28	3	10.7	2.3–28.2	28	5	17.9	6.1–36.9	28	5	17.9	6.1–36.9
6–10 d	35	15	42.9	26.3–60.6	35	19	54.3	36.6–71.2	35	19	54.3	36.6–71.2
11–15 d	34	22	64.7	46.5–80.3	34	25	73.5	55.6–87.1	34	25	73.5	55.6–87.1
16–20 d	19	14	73.7	48.8–90.9	19	14	73.7	48.8–90.9	19	15	78.9	54.4–93.9
>20 d	11	8	72.7	39.0–94.0	11	10	90.9	58.7–99.8	11	10	90.9	58.7–99.8
UCP
1–5 d	28	7	25.0	10.7–44.9	28	7	25.0	10.7–44.9	28	7	25.0	10.7–44.9
6–10 d	36	21	58.3	40.8–74.5	36	18	50.0	32.9–67.1	36	21	58.3	40.8–74.5
11–15 d	34	26	76.5	58.8–89.3	34	25	73.5	55.6–87.1	34	27	79.4	62.1–91.3
16–20 d	19	15	78.9	54.4–93.9	19	14	73.7	48.8–90.9	19	15	78.9	54.4–93.9
>20 d	11	10	90.9	58.7–99.8	11	9	81.8	48.2–97.7	11	10	90.9	58.7–99.8
VivaChek
1–5 d	25	7	28.0	12.1–49.4	25	7	28.0	12.1–49.4	25	7	28.0	12.1–49.4
6–10 d	35	22	62.9	44.9–78.5	35	22	62.9	44.9–78.5	35	22	62.9	44.9–78.5
11–15 d	30	26	86.7	69.3–96.2	30	25	83.3	65.3–94.4	30	26	86.7	69.3–96.2
16–20 d	19	15	78.9	54.4–93.9	19	14	73.7	48.8–90.9	19	15	78.9	54.4–93.9
>20 d	10	9	90.0	55.5–99.7	10	9	90.0	55.5–99.7	10	9	90.0	55.5–99.7
Wondfo
1–5 d									26	10	38.5	20.2–59.4
6–10 d									36	24	66.7	49.0–81.4
11–15 d									32	27	84.4	67.2–94.7
16–20 d									19	17	89.5	66.9–98.7
>20 d									11	9	81.8	48.2–97.7
*ELISAs*
Epitope
1–5 d	28	5	17.9	6.1–36.9	28	11	39.3	21.5–59.4	28	11	39.3	39.3–21.5
6–10 d	36	19	52.8	35.5–69.6	36	28	77.8	60.8–89.9	36	29	80.6	80.6–64.0
11–15 d	34	27	79.4	62.1–91.3	34	31	91.2	76.3–98.1	34	31	91.2	91.2–76.3
16–20 d	19	14	73.7	48.8–90.9	19	16	84.2	60.4–96.6	19	17	89.5	89.5–66.9
>20 d	11	9	81.8	48.2–97.7	11	10	90.9	58.7–99.8	11	10	90.9	90.9–58.7
In-house^a
1–5 d									28	10	35.7	18.6–55.9
6–10 d									36	26	72.2	54.8–85.8
11–15 d									34	32	94.1	80.3–99.3
16–20 d									19	17	89.5	66.9–98.7
>20 d									11	9	81.8	48.2–97.7

Specificity in 108 blood donor plasma specimens collected before July 2018
	IgM				IgG				IgM or IgG
Assay	Total n	Positive	Specificity (%)	95% CI	Total n	Positive	Specificity (%)	95% CI	Total n	Positive	Specificity (%)	95% CI
*Immunochromatographic LFAs*
Biomedomics	107	13	87.9	80.1–93.4	107	4	96.3	90.7–99.0	107	14	86.9	79.0–92.7
Bioperfectus	104	3	97.1	91.8–99.4	104	2	98.1	93.2–99.8	104	5	95.2	89.1–98.4
DecomBio	107	10	90.7	83.5–95.4	107	9	91.6	84.6–96.1	107	11	89.7	82.3–94.8
DeepBlue	108	17	84.3	76.0–90.6	108	1	99.1	94.9–100.0	108	17	84.3	76.0–90.6
Innovita	108	4	96.3	90.8–99.0	108	0	100.0	96.6–100.0	108	4	96.3	90.8–99.0
Premier	108	2	98.1	93.5–99.8	108	1	99.1	94.9–100.0	108	3	97.2	92.1–99.4
Sure	108	0	100.0	96.6–100.0	108	0	100.0	96.6–100.0	108	0	100.0	96.6–100.0
UCP	107	2	98.1	93.4–99.8	107	2	98.1	93.4–99.8	107	2	98.1	93.4–99.8
VivaChek	99	5	94.9	88.6–98.3	99	4	96.0	90.0–98.9	99	5	94.9	88.6–98.3
Wondfo									106	1	99.1	94.9–100.0
*ELISAs*
Epitope	108	3	97.2	92.1–99.4	108	10	90.7	83.6–95.5	108	11	89.8	82.5–94.8
In-house^b									108	1	99.1	94.9–100.0

Percentage of positive specimens from individuals who tested positive for non-SARS-CoV-2 viral infections and/or tested negative for SARS-CoV-2 by RT–PCR
	IgM				IgG				IgM or IgG
Assay	Total n	Positive	%	95% CI	Total n	Positive	%	95% CI	Total n	Positive	%	95% CI
*Immunochromatographic LFA*
Biomedomics	51	8	15.7	7.0–28.6	51	4	7.8	2.2–18.9	51	11	21.6	11.3–35.3
Bioperfectus	45	5	11.1	3.7–24.1	45	6	13.3	5.1–26.8	45	8	17.8	8.0–32.1
DecomBio	51	5	9.8	3.3–21.4	51	2	3.9	0.5–13.5	51	6	11.8	4.4–23.9
DeepBlue	51	14	27.5	15.9–41.7	51	7	13.7	5.7–26.3	51	14	27.5	15.9–41.7
Innovita	28	2	7.1	0.9–23.5	28	2	7.1	0.9–23.5	28	3	10.7	2.3–28.2
Premier	51	0	0.0	0.0–7.0	51	1	2.0	0.0–10.4	51	2	3.9	0.5–13.5
Sure	51	0	0.0	0.0–7.0	51	0	0.0	0.0–7.0	51	0	0.0	0.0–7.0
UCP	51	3	5.9	1.2–16.2	51	2	3.9	0.5–13.5	51	3	5.9	1.2–16.2
VivaChek	48	4	8.3	2.3–20.0	48	1	2.1	0.1–11.1	48	4	8.3	2.3–20.0
WondFo									41	0	0.0	0.0–8.6
*ELISAs*
Epitope	51	2	3.9	0.5–13.5	51	7	13.7	5.7–26.3	51	8	15.7	7.0–28.6
In-house^b									51	7	13.7	5.7–26.3

^aSamples are binned by time after patient-reported symptom onset for SARS-CoV-2 RT–PCR-positive cases. Percent of seropositivity assessed by each assay in SARS-CoV-2 RT–PCR-positive samples is reported with 95% CIs. The column ‘IgM or IgG’ refers to positivity of either isotype. Specificity is determined relative to pre-COVID-19 negative control serum samples. Percent of seropositivity assessed by each assay is reported with 95% CIs for samples from individuals who tested positive for non-SARS-CoV-2 viral infections and/or tested negative for SARS-CoV-2 by RT–PCR.
^bIn-house ELISA secondary antibody is directed against human IgG F(ab′)₂. Per the manufacturer, some cross-reactivity with IgM and IgA isotypes cannot be excluded.

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Table 2 Summary statistics for immunochromatographic LFAs and ELISAs^a

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