Table 3.

The kits cleared a EUA from FDA for SARS-CoV-2 antibody detection. The commercial kit list was retrieved from the FDA website in early May 2020 (U.SFDA, 2020a, USFDA, 2020l). Instruction for Use (IFU) and Fact Sheet for Healthcare Providers (HCP) documents were also retrieved from the same FDA website.

Entity/Company	Targeted Molecules and Kit Name	Details
Abbott Laboratories Inc.	IgG only SARS-CoV-2 IgG assay	The test can be used only in authorized laboratories on Abbott's Architect i1000SR and i2000SR instruments. This platform can run 100–200 tests/hour, being faster than RT-PCR. It is reported that the kit has a sensitivity of 100% and specificity of 99.5% (IFU). The company plans to develop an IgM test too, which would be the 4th product of the company in the market for the COVID-19 diagnosis (Cairns, 2020).
Autobio Diagnostics Co. Ltd.	IgM and IgG Anti-SARS-CoV-2 Rapid Test	This is a rapid LFA test based on a one-step capture protocol. The samples can be taken from serum or plasma. The membrane pads are decorated with anti-Spike, anti-IgM, and IgG antibodies lines, which serve as a control, IgG detection, and IgM detection lines, respectively. The spike protein-coated gold nanoparticles are employed to capture the antibodies and form a reddish color on the pads for fast, visual detection. The protocol implies that the tests are more accurate when used after around 15 days following the infection (IFU). Such a test can be used by individuals since they do not require trained personnel or sophisticated equipment.
DiaSorin Inc.	IgG only LIAISON SARS-CoV-2 S1/S2 IgG	This kit is a two-step automated immunoassay for the qualitative detection of anti-SARS-CoV-2 IgG antibodies in serum/plasma samples. The assay is based on chemiluminescent microparticle immunoassay technology (CMIA) in which the particles are functionalized with the SARS-CoV-2 antigens. Further addition of the Anti-human IgG acridinium-labeled conjugate into the incubation medium creates a chemiluminescent signal that is measured as relative light units. The positive percent agreement (PPA) was reported as 100% for 88 clinically validated positive samples that are measured after at least 14 days following the infection, whereas this value was ≤25% when tested in the first week (n = 12) (IFU). This test can only be performed at laboratories; however, the sensitivity of the test is high enough to make a decision without further confirmation.
Ortho-Clinical Diagnostics, Inc.	IgG only VITROS Immunodiagnostic Products Anti-SARS-CoV-2 IgG Reagent	This two-step kit is performed with Anti-SARS-CoV-2 IgG Reagent Pack, the Anti-SARS-CoV-2 IgG Calibrator on the ECi/ECiQ/3600 Immunodiagnostic Systems and the 5600/XT 7600 Integrated Systems, all available from Ortho-Clinical Diagnostics, Inc. In the first step, anti-SARS-CoV-2 antibodies bind to the wells that are decorated with the virus spike proteins. The wash step removes the unbound molecules from the sample environment, which is followed by the addition of the horseradish-peroxidase-linked anti IgG antibodies. If there is no spike protein-IgG complex in the sample, the second antibody will be cleared off the well with the second washing step. If positive, the addition of a final enzymatic substrate results in a color change that is measured and correlated with the virus presence. The test showed 100% negative agreement (n = 407) and 87.5% (n = 48) positive agreement (IFU). The positive agreement value of the test is relatively low that probably requires a second confirmatory test.
Mount Sinai Laboratory	IgG only COVID-19 ELISA IgG Antibody Test	The ELISA-based test kit is only authorized for use at Mount Sinai Laboratory (New York, USA), certified CLIA (1988, 42 U.S.C. §263a), to perform high complexity tests (HCP). The ELISA kits cannot be performed out of laboratory; however, they are both reliable and high throughput and thus a very efficient alternative to the RT-PCR method.
Ortho Clinical Diagnostics, Inc.	Total Antibody VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack	The SARS-CoV-2 Total Antibody kit by Ortho Clinical, Inc. is quite similar to the one other VITROS kit, listed earlier in this table except for the second step, which involves the use of horseradish peroxidase (HRP)-labeled recombinant SARS-CoV-2 antigen instead of horseradish-peroxidase-linked anti IgG antibodies. The clinical agreement of the kit was reported as 100% negative agreement (n = 400) and 83.3% positive agreement, which is less than the IgG antibody kit agreement values, provided by the same company (IFU).
Chembio Diagnostic System, Inc.	IgM and IgG DPP COVID-19 IgM/IgG System	The DPP® COVID-19 IgM/IgG System is a single-use rapid test (a version of LFA performed on a device for readout) for qualitative IgG and IgM detection in blood, serum, or plasma samples. The platform includes the DPP COVID-19 IgM/IgG Test Devices and the DPP Micro Reader/DPP Micro Reader 2 for use with the kit. For this dual antibody detection platform, the positive agreement was reported as 100% (n = 13) for both IgG and IgM (for the samples tested after the first two weeks of the infection). The negative agreements were reported as 100% for IgM and 95.9% for IgG, 95.9% for IgG, and IgM dual test line (n = 49) (IFU).
Cellex Inc.	IgM and IgG qSARS-CoV-2 IgG/IgM Rapid Test	This test is an LFA that can detect antibodies produced against the new Coronavirus. The cassette includes colloidal gold conjugated- SARS-CoV-2 antigens and rabbit IgG-gold conjugates to be spiked with the actual sample. One of the test lines contains an anti-human IgG antibody for IgG testing; the other one contains anti-human IgM antibodies for IgM detection. The control line contains anti-rabbit IgG antibodies produced in goat and work regardless of the presence of anti-SARS-CoV-2 IgG/IgM antibodies in the sample. The overall clinical agreement values were reported as 93.8% for the positive percent (n = 128), and 96% for the negative percent (n = 250) (IFU). The clinical agreement values are higher than the previous kits.

The Other Serology Kits
Supplier	Target Molecules and Kit Name	Sensitivity/Specificity	Country/Use/Reference
Aytu BioScience, Inc./Orient Gene Biotech.	IgM and IgG (COVID-19) IgM/IgG Rapid Test	The sensitivity of lgM only test is 89.2% (n = 112). The specificity is 100% (n = 14). The sensitivity of lgG & IgM test is 91.9% (n = 112), and the specificity is 100% (n = 14)	China For only professional use (Aytu BioScience Inc, 2020)
ScanWell Health/INNOVITA	IgM and IgG SARS-CoV-2 Rapid Test	87.3% sensitivity and 100% specificity in clinical trials	China For use at-home with smartphone readout (Murphy, 2020)
SD Biosensor, Inc.	IgM and IgG Standard Q COVID-19 IgM/IgG Duo Rapid Test	The positive percent value for IgM/IgG was reported as 98.1% (n = 52) for the samples measured following around two weeks of the infection. This percent was increased up10 100% following almost three weeks of the infection. The negative percent value was reported as 96.1& (n = 205).	South Korea/Point-of-care (SDBiosensor Inc., 2020)