Significance of serology testing to assist timely diagnosis of SARS-CoV-2 infections: implication from a family cluster

Figures & data

Figure 1. Chest CT images. (a) Transverse chest CT images from Case 1 showing bilateral ground-glass opacity, subsegmental areas of consolidation and subpleural line. (b) Transverse chest CT images from Case 2 showing peripheral pulmonary parenchymal ground-glass and consolidative pulmonary opacities. (c) Transverse chest CT images from Case 3 showing subsegmental areas of ground-glass opacity and consolidation. Transverse chest CT images from Case 4 (d), Case 5 (e) and Case 6 (f) were normal.

Table 1. Clinical characteristics, chest CT features and laboratory findings of the family cluster.

	Case 1	Case 2	Case 3	Case 4	Case 5	Case 6
Family relationship	Wife	Husband	Daughter	Son in law	Grandson	Granddaughter
Epidemiological history
Recent residency in Wuhan	Y	Y	N	N	Y	N
Date of leaving Wuhan	Jan 22	Jan 22	NA	NA	Jan 22	NA
Symptoms
Date of initial symptoms	Feb 3	Feb 2	Feb 3	NA	NA	NA
Fever (maximum temperature)	38.0°C	37.6°C	36.4°C	36.6°C	36.4°C	36.1°C
Oxygen saturation	95%	97%	99%	100%	100%	98%
Nasal congestion	N	Y	N	N	N	N
Cough	Y	Y	Y	N	N	N
Laboratory examination
White blood cell count (10⁹/L); (normal range 3.5-9.5)	5.01	5.11	5.16	9.83	5.85	9.72
Neutrophil count (10⁹/L); (normal range 2.0-7.5)	2.00	3.10	3.82	7.12	2.22	3.80
Lymphocyte count (10⁹/L); (normal range 0.8-4.0)	2.68	1.44	1.08	2.25	3.27	5.01
Chest CT images	Manifestation of viral pneumonia	Manifestation of viral pneumonia	Manifestation of viral pneumonia	Normal	Normal	Normal
SARS-CoV-2 RT-PCR assay§	Pos	Neg	Neg	Neg	Neg	Neg
SARS-CoV-2 RT-PCR assay after 24 h §#	ND	Neg	Neg	Neg	Pos	Neg
SARS-CoV-2-specific IgM (GICA)	Pos	Pos	Pos	Neg	Pos	Pos
SARS-CoV-2-specific IgM (ELISA)	Pos	Strong pos	Pos	Neg	Weak pos	Pos
SARS-CoV-2-specific IgG (ELISA)	Neg	Strong pos	Neg	Neg	Neg	Neg
Diagnosis	Confirmed COVID-19	Suspected COVID-19 patient*	Suspected COVID-19 patient*	COVID-19 close contact	Confirmed COVID-19	COVID-19 close contact

§Molecular assays were performed with two different SARS-CoV-2 RT-PCR kits simultaneously.

#If the result of the result of SARS-CoV-2 RT-PCR assay was negative, nasopharyngeal swabs were collected 24 h later for a second molecular assays.

*This reflected diagnosis on February 6, 2020. Follow-up molecular testing was positive for case 2 five days later and for case 3 one month later, respectively, and made COVID-19 diagnosis confirmed.

GICA= gold immunochromatography assay. ELISA= enzyme-linked immunosorbent assay. NA=not available. ND=not done. Y=Yes. N=No. Pos =positive. Neg =negative.