Evaluation of Enzyme-Linked Immunoassay and Colloidal Gold- Immunochromatographic Assay Kit for Detection of Novel Coronavirus (SARS-Cov-2) Causing an Outbreak of Pneumonia (COVID-19) (preprint)

Abstract BACKGROUND: In December 2019, a novel coronavirus (SARS-CoV-2) infected pneumonia (COVID-19) occurred in Wuhan, China. Travel-associated cases have also been reported in other countries. The number of cases has increased rapidly but laboratory diagnosis is limited. METHODS: We collect two groups of cases diagnosed with COVID-19 for experiments. One group collected 63 samples for Enzyme-linked immunosorbent assay (ELISA) IgG and IgM antibodies. The other group collected 91 plasma samples for colloidal gold-immunochromatographic assay (GICA). RESULTS: The sensitivity of the combined ELISA IgM and ELISA IgG detection was 55/63 ( 87.3%), The sensitivity of the combined GICA IgM and GICA IgG detection was 75/91 ( 82.4%), Both methods are negative for healthy controls, specificity of 100% .There is no significant difference between the sensitivity of between ELISA and GICA (IgM+ IgG). CONCLUSIONS: ELISA and GICA for specific IgM and IgG antibodies are conventional serological assays, they are simple, fast, and safe, the results can be used for clinical reference, and the huge clinical diagnosis and treatment pressure can be greatly relieved.

Comparison of throat swabs and sputum specimens for viral nucleic acid detection in 52 cases of novel coronavirus (SARS-Cov-2) infected pneumonia (COVID-19) (preprint)

Abstract Background: In December 2019, a novel coronavirus (SARS-CoV-2) infected pneumonia (COVID-19) occurred in Wuhan, China. Diagnostic test based on real-time reverse transcription polymerase chain reaction assay (qRT-PCR) was the main means of confirmation, and sample collection was mostly throat swabs, which was easy to miss the diagnosis. It is necessary to seek specimen types with higher detection efficiency and accuracy. Methods: Paired specimens of throat swabs and sputum were obtained from 54 cases, and RNA was extracted and tested for 2019-nCoV (equated with SARS-CoV-2) by qRT-PCR assay. Results: The positive rates of 2019-nCoV from sputum specimens and throat swabs were 76.9% and 44.2%, respectively. Sputum specimens showed a significantly higher positive rate than throat swabs in detecting viral nucleic acid using qRT-PCR assay (P=0.001). Conclusions: The detection rates of 2019-nCoV from sputum specimens are significantly higher than throat swabs. We suggest that sputum would benefit for the detection of 2019-nCoV in patients who produce sputum. The results can facilitate the selection of specimens and increase the accuracy of diagnosis.