Could glucose metres be used to determine whether or not someone is immune to COVID-19?

The tests that are now available to reliably evaluate antibody levels against SARS-CoV-2, the virus that is responsible for COVID-19, are expensive, time-consuming, and need complex detection equipment.

On the other hand, researchers have recently devised a simple and inexpensive antibody test that can quantify antibody levels by making use of glucose metres, which are typically employed for the purpose of determining the amount of sugar in the blood.

This novel antibody assay based on glucose metres had a sensitivity that was comparable to the present ‘gold standard’ tests, and the test may potentially be modified to be used for the diagnosis of other medical disorders.

Researchers from Johns Hopkins University have created a brand new fast assay that can identify antibodies against SARS-CoV-2 using glucose metres that are readily accessible Trusted Source. This innovative antibody assay that is based on glucose metres is both simpler to carry out and more cost-effective than the gold standard tests that are already in use.

“This work presents an innovative approach towards democratising the availability of immune protection data by enlisting commercial glucometers to quantitatively measure levels of disease-targeted antibodies,” said Dr. Jamie Spangler, a professor at Johns Hopkins University and one of the study’s co-authors.

While there are notable barriers to the development of fieldable diagnostics using off-the-shelf glucometers, studies such as these highlight a possible future where home diagnosis is as cheap and accurate as glucose sensing. Dr. Eliah Aronoff-Spencer, a professor of medicine at the University of California, San Diego, said, “While there are notable barriers to the development of fieldable diagnostics using off-the-shelf glucometers, When we reach this threshold, there will be a shift in both global monitoring and personal illness detection.

The research is presented in the journal that is published by the American Chemical Society.

determining the concentration of antibodies
The diagnostic tests for COVID-19 look for the presence of viral genetic material or proteins in the patient’s system. In contrast, tests that measure antibodies against SARS-CoV-2 can assist in determining whether or not a person has previously been exposed to the virus.

These antibodies include IgG antibodies, which are the most common form of antibody found in the blood. Other types of antibodies are also present. The production of an immune response against bacteria and viruses, including SARS-CoV-2, is significantly aided by the presence of IgG antibodies.

Notably, these IgG antibodies may be detected for a considerable amount of time following a SARS-CoV-2 infection or following vaccination with COVID-19.

Predictive power lies in the IgG antibody levels.

Source Reliable of the extent of protection against a SARS-CoV-2 infection with symptoms Therefore, determining how long immunity against COVID-19 lasts after vaccination or a previous infection can be helped by assessing the population’s antibody levels.

As a result of the appearance of novel SARS-CoV-2 variations, doubts have been expressed regarding a decline in immunity; thus, it is essential to evaluate the levels of immunological protection currently held by the community. Determining the levels of antibody protection against SARS-CoV-2 might therefore assist in guiding policy choices on the necessity of booster doses.

ELISAs, which stand for enzyme-linked immunosorbent assays, are considered the most accurate method for assessing antibody concentrations. However, in order to precisely quantify antibody levels using ELISAs, blood samples have to be sent to specialist laboratories. This is necessary since accurate detection requires the use of costly detecting gear. As a consequence of this, conducting these tests is labor-intensive, expensive, and calls for the expertise of trained technicians.

Although quick ELISA assays have been developed for clinical usage, these tests can only offer qualitative information and are still somewhat expensive. Therefore, there is a need for alternatives to ELISAs that are both more cost-effective and more widely accessible. These alternatives should be usable by both doctors and the general population.

How glucose metres aid
Tests that are compatible with glucose metres have been created by scientists as a means of overcoming the restrictions that are inherent to ELISAs. The use of glucose metres that are readily accessible on the market for the purpose of antibody detection has the potential to lower both the cost of detection and the requirement for technically competent specialists.

In these assays, antibodies or other detecting molecules are combined with the enzyme invertase, which converts sugars like sucrose into glucose. When a sucrose solution is added, the antibodies that have been linked with invertase bind to the protein of interest in the sample and create glucose as a byproduct of this reaction. A glucose metre will be able to pick up on the quantity of glucose that is created since it is related to the amount of protein that is being measured.

On the other hand, coupling antibodies with invertase has proven to be challenging. In several of their investigations, researchers have utilised intermediary chemicals such as nanoparticles in order to accomplish an indirect coupling of invertase with antibodies. On the other hand, this method can result in variable amounts of coupling and provide findings that aren’t consistent with one another.

Johns Hopkins University researchers have recently created a unique test that makes use of antibodies that are directly associated with two molecules of invertase. In order to produce these antibodies that were coupled with invertase molecules, the researchers utilised genetically engineered laboratory grown cells.

When compared to indirect coupling, genetic fusion of the antibody and the invertase enzyme ensures that a constant quantity of invertase molecules are bound to the antibody. This is in contrast to indirect coupling, which can lead to inconsistent results. These antibodies, when combined with the enzyme invertase, have the ability to attach to every human IgG antibody.

A plastic strip that has been coated with the SARS-CoV-2 spike protein is used in the innovative experiment. The SARS-CoV-2 specific antibodies selectively bind to the spike proteins covering the surface of the strip after the strip has been incubated with blood samples from people who have a history of COVID-19.

After the strip has been rinsed to eliminate any non-specific antibodies, it is then transferred, first to a solution that contains an antibody-invertase fusion protein and then to a solution that contains sucrose. This process is repeated until the strip is completely saturated with both solutions.

The antibody-invertase fusion protein is able to detect the SARS-CoV-2-specific IgG antibodies once they have been linked to the spike protein on the strip. Following this, the invertase enzyme converts the sucrose that was previously created into glucose, which may then be measured with a glucose metre. The amount of SARS-CoV-2 specific IgG antibodies present in the blood sample determines the amount of glucose that the test produces.

The researchers showed that the glucose meter-based antibody-invertase protein assay could reliably identify IgG antibodies against SARS-CoV-2, and that its performance was equivalent to that of commercially available ELISAs. This was the finding that came about as a result of the current investigation.

Possibility of the occurrence of additional illnesses
This assay’s versatility stems from the antibody-invertase fusion protein’s ability to identify all of the IgG antibodies that are generated by the human body.

“The primary objective for this technology right now is to increase production on a large scale in order to facilitate widespread use.” According to Dr. Spangler, “we want to leverage emerging data from this platform to connect illness protection with antibody levels across a large variety of people.”

Coating the strip with a protein other than the wild-type SARS-CoV-2 spike protein would allow the assay to be used to test for the presence of different conditions. For instance, antibody levels against a particular variation of SARS-CoV-2 may be measured using strips that have been coated with the spike protein derived from that version.

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