Clinical application of combined detection of SARS-CoV-2-specific antibody and nucleic acid

Table 1 Severe acute respiratory syndrome coronavirus immunoglobulin M and immunoglobulin G antibody detection result, n (%)

SARS-CoV-2; IgM antibody detection	SARS-CoV-2; IgG antibody detection		P value
	Positive	Negative
Positive	310 (99.7)	1 (0.3)	< 0.0011
Negative	282 (82.7)	59 (17.3)

¹Pearson’s χ² test, χ² = 56.46, P < 0.001. SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.

Table 2 Performance of the immunoglobulin M/immunoglobulin G antibody test kit for the diagnosis of severe acute respiratory syndrome coronavirus 2 infection with the reverse transcription-polymerase chain reaction result as a reference

	Results of IgM/IgG test (n)				IgM/IgG antibody test performance (%)
	TP	TN	FP	FN	Specificity (95%CI)	Sensitivity (95%CI)	PPV (95%CI)	NPV (95%CI)	Accuracy (95%CI)
IgM	109	205	1	128	99.5 (98.6-100.0)	46.0 (39.6-52.4)	99.1 (97.3-100.0)	61.6 (56.3-66.8)	70.9 (66.6-75.1)
IgG	227	204	2	10	99.0 (97.7-100.0)	95.8 (93.2-98.4)	99.1 (97.9-100.0)	95.3 (92.5-98.2)	97.3 (95.8-98.8)
M/G	227	203	3	10	98.5 (96.9-100.0)	95.8 (93.2-98.4)	98.7 (97.2-100.0)	95.3 (92.4-98.2)	97.1 (95.5-98.6)

SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; COVID-19: Coronavirus disease 2019; RT-PCR: Reverse transcription-polymerase chain reaction; IgM: Immunoglobulin M; IgG: Immunoglobulin G; M/G: IgM and/or IgG; TP: True positive; TN: True negative; FP: False positive; FN: False negative; PPV: Positive predictive value; NPV: Negative predictive value.