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 ... -  《-》

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 ... -  《-》

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 ... -  《-》

Serological chemiluminescence immunoassay for the diagnosis of SARS-CoV-2 infection.

Dynamic monitoring of the concentration variation of IgM and IgG in patients with SARS-CoV-2 infections and exploring their diagnostic value for coronavirus disease-19 (COVID-19). A total of 15 patients with SARS-CoV-2 infection were enrolled as the COVID-19 group, and 50 patients were enrolled as the control group. The concentrations of SARS-CoV-2-specific antibodies (IgM and IgG) were detected by a chemiluminescence immunoassay (CLIA). According to the cutoff value recommended by the manufacturer (cutoff = 10 AU/mL), the sensitivity, specificity, Youden index (YI), positive predictive value (PPV), and negative predictive value (NPV) of IgM were 60%, 100%, 60%, 100%, and 89.29%, respectively; and 86.67%, 100%, 86.67%, 100%, and 96.15%, respectively, for IgG. We reassessed the cutoff value of IgM. When the cutoff value for SARS-CoV-2 IgM was 1.83 AU/mL, the sensitivity, specificity, YI, PPV, and NPV were 93.33%, 98%, 91.33%, 93.33%, and 98%, respectively. During dynamic monitoring of the concentrations of IgM and IgG in COVID-19 patients, we found the shortest times before a patient became IgM and IgG seropositive after symptom onset were 1.5 and 2 days, respectively. The longest times were 7 and 8 days, respectively. The positive rates of SARS-CoV-2 IgM and IgG both reached 100% in 8-14 days after symptom onset. The IgM cutoff value of 1.83 AU/mL for the diagnosis of COVID-19 was much better than the cutoff suggested by the manufacturer. SARS-CoV-2 infection can be ruled out if antibodies against SARS-CoV-2 are still undetectable 14 days after symptom onset.

Lijia S ，Lihong S ，Huabin W ，Xiaoping X ，Xiaodong L ，Yixuan Z ，Pin H ，Yina X ，Xiaoyun S ，Junqi W ... -  《-》

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》