COVID-19 Antibody Test

A Renew Blood Test
Testing to see if people have HAD coronavirus, could be a game changer! - UK Government

But it has been criticized by some experts for not testing widely enough, and people have been complaining online about not having access to tests despite having symptoms.


Reasons for testing

There are two main reasons for testing people – to diagnose them individually, and to try to understand how far the virus has spread in the wider population. This second reason is referred to as “surveillance testing”.

This can involve mass testing people even if they do not have symptoms, or testing samples of people with symptoms, to get an idea of the total number of people with the virus. Positive results can also be used to try to trace the contacts of people who are known to be infected.

The failure to test more widely means that many people might be self-isolating for no good reason.


Should the UK be testing more people?

The director-general of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus said he had a “simple message” for all countries: “Test, test, test.”

He added: “We cannot stop this pandemic if we do not know who is infected”.


So why is the UK not testing more people?

Ultimately, this mainly comes down to resources. Every country is limited by how much money, equipment, and staff it has – it is not going to be possible to test every single person, so healthcare systems had have to prioritize.

“To have any impact on the spread of this virus there has to be more widespread testing out in the community…” (WHO)

South Korea, where “active community surveillance” has been far more extensive and has had “a major impact on flattening the curve and relieving pressure on stretched health services”.

Scientists are working towards a test to see whether someone has had the disease in the past, by checking for the presence of antibodies (produced by the body to fight off infection).


The Test

This test is CE marked and only for use by a professional. It identifies the body’s response to Coronavirus after the onset of infection and gives a qualitative yes/no result within 10 mins.

We only need a finger prick sample to carry out the test.

This test is able to identify infection in even mild/moderate or asymptomatic cases, with 97.8-99.6% accuracy for antibody detection.

How much does the COVID-19 antibody test cost?

The cost of the test is £75 and takes 10-15 minutes.

How long does the COVID-19 antibody test take?

Your appointment will be for 20 minutes and will be carried out while you sit in your car.

How accurate is the test?

The manufacturer of this test conducted a clinical study in Wuhan, China, where they compared the test cassette to conventional laboratory tests for COVID-19 diagnosis, which also detected the presence of IgG/IgM in 902 blood samples. They obtained the following results:

  • Sensitivity > 91%
  • Specificity > 99%
  • Accuracy > 97%

This clinical study is evidence of the usability and effectiveness of the test.

How does the test cassette work?

The test is a lateral flow immunoassay test and operates in a similar way to a pregnancy test. Embedded into the test strip are antibodies that bind to a COVID-19 specific biomarker, Immunoglobulin G (IgG), and another infection biomarker, Immunoglobulin M (IgM). When a sample (blood, serum or plasma) is added to one end of the test, it flows along the test strip and interacts with these antibodies. If the patient has contracted COVID-19, the biomarkers in their blood will bind to the antibodies on the test strip, leaving a visible test line. If the patient doesn’t have COVID-19, no biomarkers should be present in their blood and no test line will be visible. There are separate test lines for IgG and IgM and only one needs to be visible for a positive result.

What are IgG and IgM?

Immunoglobulins are antibodies themselves and are part of our immune system. When we get an infection, such as COVID-19, immunoglobulins are produced, which attach to the virus and activate the rest of the immune system to attack and clear the virus. IgM is the first immunoglobulin to be produced and is a general antibody that can bind to many different types of pathogens. The presence of IgM is an indicator of early infection. IgG is a more specialised antibody that specifically binds to the SARS-CoV-2 virus. The presence of IgG is an indicator of later-stage infection (usually 7 days or longer after infection).

Is the test specific for COVID-19?

The IgG that the test detects is specific to COVID-19, so a positive result would indicate COVID-19 infection. Although the IgM is a more generalised antibody, its presence, combined with IgG and/or the common symptoms of COVID-19, would also indicate infection with the novel SARS-CoV-2 virus. The test can be used for primary and secondary diagnosis of COVID-19.

What samples can I use?

The test cassette will work with whole blood, plasma or serum. Capillary blood is the easiest to obtain via a finger pinprick, however, venous blood obtained via venepuncture is also suitable. The type of sample will not affect the sensitivity or accuracy of the test.

So can the test detect asymptomatic patients?

Yes, the test will be able to detect IgM/IgG in asymptomatic people, as they will have an immune response even though they don’t display symptoms. The timeline of infection will be the same as someone displaying symptoms.

Do any medications, drugs or other proteins in the blood affect the test result?

To date the test kit manufacturer has tested numerous common pharmaceuticals, none of which have interfered with the test. Also, Rheumatoid Factor does not interfere with the test, hence they currently see no cross-reactivity issues.

Will IgG and IgM remain in the blood after I’ve recovered from COVID-19?

There is some evidence that IgG/IgM remains in the blood after recovery to prevent reinfection. We have tested some patients and noticed that they still test positive for at least 33 days after first displaying symptoms. You won’t be infectious after you recover, even if you test positive, but you should still be cautious as long term immunity has not yet been confirmed and reinfection may still occur.

Can pregnant or breast feeding women be tested?

Yes, there is no harm to the mother or baby when performing a test.

Is there anyone that shouldn’t be tested?

No, the more people that are tested, the better it will be to understand the spread of the virus, which will result in better measures being taken to prevent its spread. However, as the test requires a blood sample, anyone with a blood-related health condition (such as haemophilia) should discuss this with a healthcare professional before performing a test.

Is the test CE marked? Does it have IVD (in vitro diagnostic device) certification?

Yes, the COVID-19 test is CE marked for professional use and is therefore a registered in vitro diagnostic device.

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