COVID-19 (SARS-CoV-2) Rapid Detection Principle | 新冠病毒快速檢驗原理介紹

COVID-19 (SARS-CoV-2) Rapid Test Detection Principle

The number of cases of COVID-19 (SARS-CoV-2) infections in China and worldwide is rising dramatically. Reliable COVID-19 diagnoses on a large scale are increasingly needed. The presence of viruses is generally confirmed by RT-qPCR, which detects the coronavirus' RNA. This test is most sensitivite and reliable. However, this test is time consuming, ie. 4-6 hours are required to get test results. Detection of COVID-19 antigen or antibodies through lateral flow immunoassay could dramatically shorten testing time from 4-6 hrs (RT-qPCR) to 10-15 mins. Detection of COVID-19 antigen can be used to confirm very recent or active infections. Detection of antibodies can be used both for diagnosis and population surveillance.

COVID-19 (SARS-CoV-2) Antigen Rapid Detection Kit (lateral flow immunoassay)

Detection of viral infections can be obtained in the early stages of a disease by detection of viral antigens directly in the clinical specimen.

Lateral flow immunoassay design for COVID-19 (SARS-CoV-2) antigens detection:

Sample Pad: acts as absorption process, and in some cases contains a filter, to ensure the accurate and controlled flow of the sample.
Cnjugate Pad: stores the Gold conjugated COVID-19 (SARS-CoV-2) antibody, will recognize the target antigen (such as spike protein) in sample. If the virus is present, the conjugated SARS-CoV-2 antibody will bind to the virus and continue to migrate along the test.
Test Line: prints anti-COVID-19 (SARS-CoV-2) antibody, also recognize the target antigen (such as spike protein) in sample. As the sample moves along the device, the anti-COVID-19 (SARS-CoV-2) antibody situated on the nitrocellulose membrane will bind to the target antigen at the test line. A coloured line will form duo to the same target antigens were bound by Gold conjugated COVID-19 (SARS-CoV-2) antibody.
Control Line: prints secondary antibody, recognize the Fc/Fab/or H+L chain of Gold conjugated COVID-19 (SARS-CoV-2) antibody. A coloured line will form duo to Gold conjugated COVID-19 (SARS-CoV-2) antibody.
Absorbent Pad: The sample will pass through the nitrocellulose membrane into the absorbent pad. The absorbent pad will absorb the excess sample.

COVID-19 (SARS-CoV-2) IgG/IgM Rapid Test Kit (lateral flow immunoassay)

Detection of IgM/IgG after viral infections can be obtained in the mid- or late stages of a disease by detection of IgM/IgG specific recognize to viral antigens in human serum, plasma, whole blood, or finger prick samples. In general, human body generates IgM/IgG against to COVID-19 (SARS-CoV-2) after 7-14 days virus infection. IgG/IgM Rapid Test will easily show negative before IgG/IgM were generated.

Lateral flow immunoassay design for COVID-19 (SARS-CoV-2) IgG/IgM dual detection:

Sample Pad: acts as absorption process, and in some cases contains a filter, to ensure the accurate and controlled flow of the sample.
Conjugate Pad: stores the Gold conjugated COVID-19 (SARS-CoV-2) antigens, such as Nucleocapsid Protein or Spike Protein or combination of Nucleocapsid Protein and Spike Protein. The antigens will recognize by IgM/IgG that were generated by patients after infection. If the specific IgM/IgG is present, the conjugated COVID-19 (SARS-CoV-2) ntigens will be bound to IgM/IgG and continue to migrate along the test. And Gold conjugated Rabbit IgG serve as a control.
Test Line: prints anti-Human IgM antibody and anti-Human IgG antibody, recognize Human IgM and Human IgG in sample. As the sample moves along the device, the anti-Human IgM antibody and anti-Human IgG antibody situated on the nitrocellulose membrane will bind to the Human IgM and Human IgG at the test line. A coloured line will form only if Gold conjugated COVID-19 (SARS-CoV-2) antigens were bound to Human IgM/IgG.
Control Line: prints secondary antibody, recognize the Fc/Fab/or H+L chain of Gold conjugated Rabbit IgG. A coloured line will form duo to Gold conjugated Rabbit IgG.
Absorbent Pad: The sample will pass through the nitrocellulose membrane into the absorbent pad. The absorbent pad will absorb the excess sample.

COVID-19 (SARS-CoV-2) RNA Detection Kit (RT-qPCR)

Assays detecting viral nucleic acids are more sensitive than antigen detection tests because of a tremendous amplification of gene segments obtained by the polymerase chain reaction (PCR). So far such assays are time consuming and expensive and are mainly used in specific clinical situations.

Using special primers and probes, the viral nucleic acid DNA / RNA in the sample is subjected to real-time PCR or one-step reverse transcription fluorescent quantitative polymerization Enzyme chain reaction (One-step RT real-time PCR) to amplify DNA fragments to screen samples for viruses. The primers and probes used are designed according to the virus sequence. This method requires a fluorescent quantitative polymerase chain reaction instrument, which takes an average of 2-4 hours.

Real-time RT-PCR Primer and Probe Information

Name	Description	Oligonucleotide Sequence (5’>3’)	Label1	Working Conc.
2019-nCoV_N1-F	2019-nCoV_N1 Forward Primer	5’-GAC CCC AAA ATC AGC GAA AT-3’	None	20 µM
2019-nCoV_N1-R	2019-nCoV_N1 Reverse Primer	5’-TCT GGT TAC TGC CAG TTG AAT CTG-3’	None	20 µM
2019-nCoV_N1-P	2019-nCoV_N1 Probe	5’-FAM-ACC CCG CAT TAC GTT TGG TGG ACC-BHQ1-3’	FAM, BHQ-1	5 µM
2019-nCoV_N2-F	2019-nCoV_N2 Forward Primer	5’-TTA CAA ACA TTG GCC GCA AA-3’	None	20 µM
2019-nCoV_N2-R	2019-nCoV_N2 Reverse Primer	5’-GCG CGA CAT TCC GAA GAA-3’	None	20 µM
2019-nCoV_N2-P	2019-nCoV_N2 Probe	5’-FAM-ACA ATT TGC CCC CAG CGC TTC AG-BHQ1-3’	FAM, BHQ-1	5 µM
2019-nCoV_N3-F	2019-nCoV_N3 Forward Primer	5’-GGG AGC CTT GAA TAC ACC AAA A-3’	None	20 µM
2019-nCoV_N3-R	2019-nCoV_N3 Reverse Primer	5’-TGT AGC ACG ATT GCA GCA TTG-3’	None	20 µM
2019-nCoV_N3-P	2019-nCoV_N3 Probe	5’-FAM-AYC ACA TTG GCA CCC GCA ATC CTG-BHQ1-3’	FAM, BHQ-1	5 µM
RP-F	RNAse P Forward Primer	5’-AGA TTT GGA CCT GCG AGC G-3’	None	20 µM
RP-R	RNAse P Reverse Primer	5’-GAG CGG CTG TCT CCA CAA GT-3’	None	20 µM
RP-P	RNAse P Probe	5’-FAM – TTC TGA CCT GAA GGC TCT GCG CG – BHQ-1-3’	FAM, BHQ-1	5 µM

https://www.cdc.gov/coronavirus/2019-ncov/lab/rt-pcr-panel-primer-probes.html

With the now global outbreak of COVID-19, SARS-CoV-2 early diagnostics and infection prevention and control has become critical. ACE Biolabs can provide the following products lines for SARS-CoV-2 (2019-nCoV, COVID-19 virus) research:

COVID-19 (SARS-CoV-2) Rapid Detection Principle | 新冠病毒快速檢驗原理介紹 2020/04/07