Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Apr 30;128:104393.
doi: 10.1016/j.jcv.2020.104393. Online ahead of print.

Clinical Evaluation of an Immunochromatographic IgM/IgG Antibody Assay and Chest Computed Tomography for the Diagnosis of COVID-19

Free PMC article

Clinical Evaluation of an Immunochromatographic IgM/IgG Antibody Assay and Chest Computed Tomography for the Diagnosis of COVID-19

Kazuo Imai et al. J Clin Virol. .
Free PMC article


Background: We evaluated the clinical performance of an immunochromatographic (IC) IgM/IgG antibody assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) and chest computed tomography (CT) for the diagnosis of Coronavirus disease 2019 (COVID-19).

Methods: We examined 139 serum specimens collected from 112 patients with COVID-19 and 48 serum specimens collected from 48 non-COVID-19 patients. The presence of IgM/IgG antibody for SARS-COV2 was determined using the One Step Novel Coronavirus (COVID-19) IgM/IgG Antibody Test. Chest CT was performed in COVID-19 patients on admission.

Findings: Of the139 COVID-19 serum specimens, IgM was detected in 27.8 %, 48.0 %, and 95.8 % of the specimens collected within 1 week, 1-2 weeks, and >2 weeks after symptom onset and IgG was detected in 3.3 %, 8.0 %, and 62.5 %, respectively. Among the 48 non-COVID-19 serum specimens, 1 generated a false-positive result for IgM. Thirty-eight of the 112 COVID-19 patients were asymptomatic, of whom 15 were positive for IgM, and 74 were symptomatic, of whom 22 were positive for IgM and 7 were positive for IgG. The diagnostic sensitivity of CT scan alone and in combination with the IC assay was 57.9 % (22/38) and 68.4 % (26/38) for the asymptomatic patients and 74.3 % (55/74) and 82.4 % (61/74) for the symptomatic patients, respectively.

Conclusion: The IC assay had low sensitivity during the early phase of infection, and thus IC assay alone is not recommended for initial diagnostic testing for COVID-19. If RT-qPCR is not available, the combination of chest CT and IC assay may be useful for diagnosing COVID-19.

Keywords: COVID-19; Chest CT scan; Immunochromatographic assay; SARS-CoV-2.

Conflict of interest statement

Declaration of Competing Interest The authors declare that they have no conflicts of interests.

Similar articles

See all similar articles


    1. Huang C., Wang Y., Li X., Ren L., Zhao J., Hu Y. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395:497–506. - PMC - PubMed
    1. Bai H.X., Hsieh B., Xiong Z., Halsey K., Choi J.W., Tran T.M.L. Performance of radiologists in differentiating COVID-19 from viral pneumonia on chest CT. Radiology. 2020 doi: 10.1148/radiol.2020200823. - DOI - PMC - PubMed
    1. Huang P., Liu T., Huang L., Liu H., Lei M., Xu W. Use of chest CT in combination with negative RT-PCR assay for the 2019 novel coronavirus but high clinical suspicion. Radiology. 2020 doi: 10.1148/radiol.2020200330:200330. - DOI - PMC - PubMed
    1. Pan F., Ye T., Sun P., Gui S., Liang B., Li L. Time course of lung changes on chest CT during recovery from 2019 novel coronavirus (COVID-19) pneumonia. Radiology. 2020 doi: 10.1148/radiol.2020200370:200370. - DOI - PMC - PubMed
    1. Shi H., Han X., Jiang N., Cao Y., Alwalid O., Gu J. Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study. Lancet Infect. Dis. 2020;20(4):P425–P434. doi: 10.1016/S1473-3099(20)30086-4. - DOI - PMC - PubMed