COVID-19 IgG/IgM Rapid Test

Published on 02/09/2020

Watch the video Tutorial and learn how it works.

COVID-19 IgG/IgM Rapid Test

COVID-19 IgG/IgM Rapid Test is a CE Certified immunochromatographic assay for the qualitative and simultaneous detection of immunoglobulin G and M antibodies against SARS-CoV-2 in human whole blood, serum or plasma specimens. For professional use only.

Are you interested in buying our COVID-19 IgG/IgM Rapid Test kit? Please write to info@primahometest.com for further information.

Principle of the Test

The Test is a qualitative membrane based lateral flow immunochromatographic assay for the detection of IgG and IgM antibodies against SARS-CoV-2 in whole blood, serum or plasma specimen. The test combines an IgG and an IgM component, corresponding to two lines on the test strip positioned in the test cassette. During testing anti-SARS-CoV-2 IgG and IgM possibly present in the specimen react with the reagents and the nanoparticles present in the test. The mixture chromatographically migrates upward by capillary action interacting with the two test line regions resulting in the appearance of a coloured line, if the specimen contains IgM and/or IgG antibodies to SARS-CoV-2. If antibodies are not present in the specimen, no coloured line will appear in either test line regions, indicating a negative result. To serve as a procedural control, a coloured line will always appear in the Control (C) line region, indicating that the test procedure has been performed properly and that test components have operated as intended.

COVID-19 IgG/IgM Rapid Test is dedicated to healthcare professionals with the aim to support them in the COVID-19 emergency management, receiving quick answers about the health status of their patients:
- high Sensitivity and Specificity standards, when compared to a PCR Methodology;
- safe and accurate results in just 10 minutes;
- easy to use and to read.

Why using a serological test for COVID-19?

The use of a COVID-19 serological device is important because it allows to identify people potentially affected by SARS-CoV-2 and then take precautionary isolation measures in order to reduce further spread of the virus.
For this virus the incubation period is between 1 and 14 days, with a prevalence of 3 to 7 days, after which the first symptoms start to appear.

Figure 1

Sethuraman et al., show the trend over time of the detection of diagnostic tests for SARS-CoV-2. The detection increases after the onset of the first symptoms (Figure 1) reaching a peak detection for nasopharyngeal swab in the first week after the onset of symptoms and then decreases steadily. Contrary to this, IgM and IgG antibodies to SARS-CoV-2 appear in the serum or plasma of infected individuals from a few days up to 2 weeks after these symptoms and, while IgM levels decrease after the end of the infection, IgG levels remain high and therefore detectable.

For this reason, these tests are an essential tool to control both asymptomatic individuals, possibly exposed to the virus recently, and for seroprevalence investigations. In the first case, these tests can be considered as tools to support molecular tests (nasopharyngeal swabs followed by PCR tests), as they would allow to know the prevalence of the virus in a certain place (class, workplace and similar), in order to take isolation measures, thus reducing a possible asymptomatic spread. The seroprevalence studies instead, are studies in which a representative sample of the population is tested. Thanks to these analyses it is possible to know the real lethality of the disease, the geographical spread and the spread in different age groups. This information, are indications to be considered useful especially to plan when, how and how much to loosen the restrictive measures.

How does the Test work?

View the video Tutorial and follow the procedure.

A) Collect the blood sample:
1. Whole blood (fingerstick and venous sampling): fill the blood collecting pipette and transfer 20μL of whole blood sample into the sample well of the test cassette. As an alternative to the blood collecting pipette, 20μL of sample from venous sampling can be dispensed with a laboratory micropipette.
2. Serum and plasma: Transfer 10μL of sample to the sample well with a laboratory micropipette.

B) Apply two drops of diluent to the sample well, approximately 80μL, then wait for 10 minutes and then read the results. The results are valid for up to 20 minutes after adding the diluent. Beyond 20 minutes the results should not be considered.

Results interpretation

Positive IgG Results: Two coloured lines appear at the C (Control) and IgG signs, none at the IgM one. Contact the COVID-19 emergency reference number in your country and follow the instructions.

Positive IgM Results: Two coloured lines appear at the C (Control) and IgM signs, none at the IgG sign. Contact the COVID-19 emergency reference number in your country and follow the instructions.

Positive IgG/IgM Results: Three coloured lines appear at the C (Control), IgG and IgM signs. Contact the COVID-19 emergency reference number in your country and follow the instructions.

Negative Results: A coloured line appears at the C (Control) sign and none at the IgG and IgM ones.

The COVID-19 IgG/IgM Rapid Test will only indicate the presence of IgG and IgM antibodies to SARS-CoV-2 in the specimen and should not be used as the sole criteria for the diagnosis of SARS-CoV-2 infections. The results obtained with this test should be considered with other clinical findings from other laboratory tests and evaluations.

Publications

COVID-19 IgG/IgM Rapid Test has been used in several clinical studies at various European research centres and hospitals, resulting in the following publications:

- “COVID-19 and lombardy: TESTing the impact of the first wave of the pandemic”, L. Perico et al., EBioMedicine (2020), 61:103069, DOI:https://doi.org/10.1016/j.ebiom.2020.103069.
The aim of this study was to perform a cross-sectional study to assess the prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in 423 workers in Bergamo province who returned to the workplace after the end of the Italian lockdown on 5th May 2020.
As a secondary aim of the study, we validated a lateral flow immunochromatography assay (LFIA) for the detection of anti-SARS-CoV-2 antibodies. Results show the prevalence of SARS-CoV-2 infection in the province of Bergamo reached 38.5%, significantly higher than has been reported for most other regions worldwide. Among all the seropositive individuals, very few tested positive for SARS-CoV-2 in nasopharyngeal swabs, with a low viral load and no infective potential in cultured cells. The cumulative seroprevalence allowed to estimate that the actual diffusion of SARS-CoV-2 in Bergamo was 26-times higher than that reported from official data, indicating that the 96% of COVID-19 cases were underestimated. Based on these numbers, the fatality rate of COVID-19 in the Bergamo area decreases to around the 1%, significantly lower than the 20% from the official data. Finally, results show LFIAs as a valuable tool for rapid serologic surveillance of COVID-19 for population studies, showing a specificity and sensitivity for IgG anti-SARS-CoV-2 of 98% and 92%, respectively.

- “SARS-CoV-2 seroprevalence trends in healthy blood donors during the COVID-19 Milan outbreak”, by L. Valenti et al., Submitted to Eurosurveillance, (medRxiv preprint doi: https://doi.org/10.1101/2020.05.11.20098442).
The aim of this study was to examine the seroprevalence of SARS-CoV-2 infection in healthy asymptomatic adults, the risk factors, and laboratory correlates in the Milan metropolitan area. The seroprevalence was detected with a lateral flow immunoassay, detecting anti-nucleocapsid antibodies to SARS-CoV-2. Participants included a random sample of blood donors since the start of the outbreak (February 24th to April 8th 2020, n=789).
Results show that at the start of the outbreak, the overall seroprevalence of SARS-CoV-2 was 4.6% (2.3 to 7.9; P<0.0001 vs. 120 historical controls). During the study period characterized by a gradual implementation of social distancing measures, there was a progressive increase in seroprevalence to 7.1% (4.4 to 10.8), due to a rise in IgG+ to 5% (2.8 to 8.2; P=0.004 ) but not of IgM+ (P=NS).<br>In conclusion the study suggests that the SARS-CoV-2 infection was already circulating in Milan at the outbreak start, with up to 10% of healthy individuals having evidence of seroconversion.

- “Rapid antibody testing for SARS-Cov-2 in asymptomatic and paucisymptomatic healthcare professionals in Hematology and Oncology units identifies undiagnosed infections" by P. Corradini et al, Hemasphere (2020) 4:3(e408). http://dx.doi.org/10.1097/.
The aim of the study was to detect the prevalence of occult infections at the Hemat-Onc department of the Milano National Cancer Institute. These undocumented cases are likely to represent a real threat for patients, colleagues and also family contacts.
Preliminary data from the Italian Society of Hematology suggest that also in the hematology and bone marrow transplantation setting, mortality for COVID-19 infected patients, seems at least 30%. Thus, stringent control measures in Hemat-Onc units are of utmost importance to keep them COVID-free.
Participants included asymptomatic and paucisymptomatic workers (doctors, nurses, paramedics and staff members) and the serology status was checked with a lateral-flow immunoassay detecting the presence of anti-nucleocapsid antibodies to SARS-CoV-2. The presence of viral RNA was searched by reverse transcription polymerase chain reaction (RT-PCR) in NPS (nasopharyngeal swab) of seropositive cases only.
Results have shown that the prevalence of asymptomatic/paucisymptomatic healthcare workers in the Hemat-Onc Units at the Milano National Cancer Institute with a positive serology is 9.4% and that 31.8% of them had a confirmed diagnosis of COVID-19 by RT-PCR of SARS CoV- 2 RNA in NPS. In conclusion, the screening with repeated serologic testing allows the identification of occult infected workers and limits the use of NPS.

Bibliography

1. European Centre for Disease Prevention and Control, Disease background of COVID-19 (https://www.ecdc.europa.eu/en/2019-ncov-backgrounddisease)

2. WHO Director-General's opening remarks at the media briefing on COVID-19 - 11 March 2020 (https://www.who.int/dg/speeches/detail/who-directorgeneral-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020)

3. Xiao AT, Gao C, Zhang S. Profile of specific antibodies to SARSCoV-2: the first report. J Infect 2020. doi: 10.1016/j.jinf.2020.03.012

4. Zhao J, Yuan Q, Wang H, Liu W, Liao X, Su Y, et al. Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019. medRxiv.2020:2020.03.02.20030189

5. Long Q-x, Deng H-j, Chen J, Hu J, Liu B-z, Liao P, et al. Antibody responses to SARS-CoV-2 in COVID-19 patients: the perspective application of serological tests in clinical practice. medRxiv. 2020:2020.03.18.20038018

6. Sethuraman N, Jeremiah SS, Ryo A. “Interpreting Diagnostic Tests for SARS-CoV-2.” JAMA. Published online May 06, 2020. DOI:10.1001/jama.2020.8259

7. Sun et al., “Kinetics of SARS-CoV-2 specific IgM and IgG responses in COVID-19 patients” Emerging Microbes & Infections, 2020, 9:1, DOI:10.1080/22221751.2020.1762515