A Peptide-Based Magnetic Chemiluminescence Enzyme Immunoassay for Serological Diagnosis of Coronavirus Disease 2019.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel β-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection. In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2. To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively. Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.

Cai XF ，Chen J ，Li Hu J ，Long QX ，Deng HJ ，Liu P ，Fan K ，Liao P ，Liu BZ ，Wu GC ，Chen YK ，Li ZJ ，Wang K ，Zhang XL ，Tian WG ，Xiang JL ，Du HX ，Wang J ，Hu Y ，Tang N ，Lin Y ，Ren JH ，Huang LY ，Wei J ，Gan CY ，Chen YM ，Gao QZ ，Chen AM ，He CL ，Wang DX ，Hu P ，Zhou FC ，Huang AL ，Wang DQ ... -  《-》

Evaluations of the serological test in the diagnosis of 2019 novel coronavirus (SARS-CoV-2) infections during the COVID-19 outbreak.

Lin D ，Liu L ，Zhang M ，Hu Y ，Yang Q ，Guo J ，Dai Y ，Xu Y ，Cai Y ，Chen X ，Huang K ，Zhang Z ... -  《-》

Rapid Serological Assays and SARS-CoV-2 Real-Time Polymerase Chain Reaction Assays for the Detection of SARS-CoV-2: Comparative Study.

Real-time polymerase chain reaction (RT-PCR) testing for the identification of viral nucleic acid is the current standard for the diagnosis of SARS-CoV-2 infection, but technical issues limit its utilization for large-scale screening. Serological immunoglobulin M (IgM)/IgG testing has been proposed as a useful tool for detecting SARS-CoV-2 exposure. The objective of our study was to compare the results of the rapid serological VivaDiag test for SARS-CoV-2-related IgM/IgG detection with those of the standard RT-PCR laboratory test for identifying SARS-CoV-2 nucleic acid. We simultaneously performed both serological and molecular tests with a consecutive series of 191 symptomatic patients. The results provided by a new rapid serological colorimetric test for analyzing IgM/IgG expression were compared with those of RT-PCR testing for SARS-CoV-2 detection. Of the 191 subjects, 70 (36.6%) tested positive for SARS-CoV-2 based on RT-PCR results, while 34 (17.3%) tested positive based on serological IgM/IgG expression. Additionally, 13 (6.8%) subjects tested positive based on serological test results, but also tested negative based on RT-PCR results. The rapid serological test had a sensitivity of 30% and a specificity of 89% compared to the standard RT-PCR assay. Interestingly, the performance of both assays improved 8 days after symptom appearance. After 10 days had passed since symptom appearance, the predictive value of the rapid serological test was higher than that of the standard molecular assay (proportion of positive results: 40% vs 20%). Multivariate analysis showed that age >58 years (P<.01) and period of >15 days after symptom onset (P<.02) were significant and independent factors associated with serological test positivity. The rapid serological test analyzed in this study seems limited in terms of usefulness when diagnosing SARS-CoV-2 infection. However, it may be useful for providing relevant information on people's immunoreaction to COVID-19 exposure.

Paradiso AV ，De Summa S ，Loconsole D ，Procacci V ，Sallustio A ，Centrone F ，Silvestris N ，Cafagna V ，De Palma G ，Tufaro A ，Garrisi VM ，Chironna M ... -  《JOURNAL OF MEDICAL INTERNET RESEARCH》

Evaluation of performance of two SARS-CoV-2 Rapid IgM-IgG combined antibody tests on capillary whole blood samples from the fingertip.

Prazuck T ，Colin M ，Giachè S ，Gubavu C ，Seve A ，Rzepecki V ，Chevereau-Choquet M ，Kiani C ，Rodot V ，Lionnet E ，Courtellemont L ，Guinard J ，Pialoux G ，Hocqueloux L ... -  《PLoS One》

Clinical application of Chemiluminescence Microparticle Immunoassay for SARS-CoV-2 infection diagnosis.

The unsatisfactory accuracy and capacity of real time RT-PCR depends on several unavoidable reasons, which cannot meet the demands for COVID-19 diagnosis. 206 serum samples were collected from patients who were treated in the General Hospital of the Central Theater Command of the PLA between January 18 and April 4, 2020. 270 serum samples from healthy blood donors were used as control. IgM and total antibodies (Ab) against SARS-CoV-2 were detected by Chemiluminescence Microparticle Immunoassay (CMIA). Among the 206 patients, the positive rate of IgM and Ab were 149/206 (72.3 %) and 187/206 (90.8 %), respectively. And the specificity of IgM and Ab detection were 99.3 % and 98.9 %, respectively. The sensitivity of CMIA for Ab detection was significantly higher than that of IgM. An increase of the positive rate and S/CO value for detecting IgM and Ab accompanied with the increasing of days post-disease onset (d.p.o.) were observed. The positive rate of Ab detected by CMIA increased rapidly after 7 d.p.o., while that of IgM was obviously increased after 14 d.p.o.. In addition, the age and gender of these patients did not affect the seroconversion and titer of antibodies during the whole course. The disease-severity of patients had no effect on the seroconversion of antibodies. However, the critical patients possessed a much higher antibody titers than the no-critical cases after 14 d.p.o.. The CMIA can provide important complementation to nucleic acid assay and help to enhance the accuracy and capacity of diagnosis of SARS-CoV-2 infection.

Liu W ，Kou G ，Dong Y ，Zheng Y ，Ding Y ，Ni W ，Wu W ，Tang S ，Xiong Z ，Zhang Y ，Liu L ，Zheng S ... -  《-》