When to test: At least 14 days after onset of COVID-19 symptoms, or 14 days after last vaccine dose.
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COVID-19 Antibody Test

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Have you recently had COVID-19 and recovered, or have you been vaccinated? This antibody test checks whether IgG antibodies against the spike protein of the SARS-CoV-2 virus are present in your blood after an infection or vaccination. This indicates whether an immune reaction has taken place that could protect the body against a future infection. This test also indicates whether you have had a natural infection in recent weeks by detecting antibodies against the nucleocapsid protein. This test is different from a PCR test, which involves the detection of a current infection with SARS-CoV-2.

Test name: EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA

Testing method: Dried Blood Spot test based on a finger prick

What do we test for?

Anti-SARS-CoV-2 Antibodies: Nucleocapsid (N) Protein Anti-SARS-CoV-2 Antibodies: Spike (S) Protein
  • Results within 24 hours after arrival at the lab
  • Ordered before 18:00, shipped today
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  • Results within 24 hours after arrival at the lab
  • Ordered before 18:00, shipped today
  • Free shipping on every order
  • Easy to use from home
  • Professional analysis in a medically certified laboratory
  • Most affordable home test provider
About the Test


COVID result mockup

Understanding your test results

Antibodies against the Nucleocapsid Spike (S) Protein 

  • An S protein antibody titre of <35.2 BAU/ml means that no antibodies against the coronavirus have been found in your blood.
  • An S protein antibody titre ≥35.2 BAU/ml means that your body has produced antibodies against the coronavirus from either vaccination or natural infection. The test cannot differentiate between antibodies from vaccination and antibodies from natural infection. The higher the value, the higher the number of antibodies.

Antibodies against the Nucleocapsid (N) Protein

  • An N protein antibody ratio of < 1.1  means that you have not had a natural SARS-CoV-2 infection in recent weeks/months
  • An N protein antibody ratio of ≥ 1.1  means that you have had a natural SARS-CoV-2 infection in recent weeks/months.

How results are shared

We understand that blood test results can be confusing. That’s why at Homed-IQ, we make it easy for you to interpret your results and understand what’s going on inside your body.

In your personal online dashboard, you can view your test results and access clear and simple explanations about individual health markers. All test results are verified by our qualified medical team before being sent to you.

The result of your antibody test is shown on a scale from which you can easily see how your results compare to the highest and lowest possible results.

Scientists are still determining how COVID-19 antibody levels affect immunity and the risk of reinfection. However, it is proven that people with COVID-19 antibodies are less likely to develop another infection than those without these antibodies. The durability of this immunity has yet to be determined. The QuantiVac antibody test allows users to measure their antibody levels at different stages after vaccination, which can be very helpful in getting a better understanding of COVID-19 immunity over time.

About the Test


When you become infected with the SARS-CoV-2 virus, your body has a natural defence mechanism, as with all viral infections. In this reaction, your immune system is activated to defend itself against the virus. After an average of 10 to 14 days memory antibodies (IgG) will be produced. While IgA and IgM antibodies disappear from the bloodstream over time, IgG stays in the body longer and ensures that the immune response to the same virus will be much faster and more effective than the first exposure. This means that the immune system can respond immediately and provides protection against the virus.

The strength of the antibody response depends on several factors, including age, disease severity, and certain medications or infections that may suppress the immune system. It can take 2 to 3 weeks for your body to produce antibodies in sufficient quantities to detect them. During vaccination, the immune system is trained to optimize the immune response. The formation of IgG antibodies makes you (possibly) immune to another attack from the same virus. However, it is not yet clear how long protection will last. With this test, we can demonstrate whether and to what extent IgG antibodies are produced in your body after infection with COVID-19 or after vaccination.

What’s in the test kit?

The test kit contains instructions for use, a blood collection card, alcohol wipes, band-aids, lancets to collect a small blood sample, an alcohol-free wipe, and a protective pouch.

The Test Process

This test uses Dried Blood Spot (DBS) testing technology to obtain a blood sample. The test kit will be delivered to your home and contains all materials needed to complete the sample. To collect the sample, you must prick yourself using the enclosed disposable lancets and deposit a small quantity of blood onto the paper blood spot card provided. After collecting the sample, send the materials to one of our certified partner laboratories by using the prepaid return envelope. Once the test results are available, they will be reviewed by a doctor and shared with you. All of our tests are CE certified laboratory tests and are absolutely not ‘quick tests’!

About the Test

Homed-IQ’s COVID-19 Antibody Test is developed by EUROIMMUN for the quantitative detection of IgG antibodies against the coronavirus (anti-SARS-CoV-2). Using a blood sample that is collected from home, this test can detect antibodies against the SARS-CoV-2 virus, which can indicate possible immunity against future infections. The high specificity of the test is critical to reliably determine whether a person has been exposed to the virus and whether they have developed antibodies.

Homed-IQ’s COVID-19 Antibody Test measures the quantity of two types of IgG antibodies in the blood: the spike (S) and nucleocapsid (N) proteins. The S protein of the SARS-CoV-2 virus contains the receptor-binding domain (RBD), which mediates the attachment of the virus to the human host cells. IgG antibodies against this protein are considered an indicator of possible immunity, since more than 90% of the neutralizing antibodies in COVID-19 patients are directed against the S protein’s receptor-binding domain. The S protein is also the target protein of most vaccines against SARS-CoV-2. Hence, anti-S-antibodies can be detected after both natural infections and vaccinations with S protein based vaccines such as Pfizer, Janssen, and Moderna. Therefore, differentiating whether S protein antibodies are from an infection or from vaccination is not possible.

The N protein is considered the antigen with the highest immunodominance within the family of coronaviruses, including the SARS-CoV-2 virus. Since most approved vaccines are based on the S protein and do not contain N protein, antibodies against N proteins are usually associated with natural infections. Therefore vaccination against SARS-CoV-2 will not produce a positive test result for N protein antibodies.

It should be noted it can take 2 to 3 weeks for your body to produce the correct antibodies in sufficient quantities to detect them. The test is reliable for the detection of IgG antibodies when taken 14 days after the onset of the first symptoms of COVID-19 or 14 days after vaccination.


How does it work?

Order your test
After you have placed the order, your test kit will be delivered within a few days in discreet packaging.
Activate and take your sample
After the online activation of the test kit, you can collect the test sample and return it to the lab for analysis.
Receive your test result
A certified laboratory will analyze your test and share it with our medical team, after which you receive the results in your account.

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Frequently asked questions

Who should not use this antibody test?
  1. People under 18 years old
  2. People who are currently experiencing severe symptoms of COVID-19. In that case, we recommend that you seek immediate medical attention.
  3. Anyone with symptoms of COVID-19 arising less than 14 days ago
  4. Anyone previously exposed to the virus who was vaccinated less than 14 days ago
I had a confirmed case of COVID-19, but my test result says I have low or no antibodies. Why is that?
  • Scientists are still investigating the effects of the cellular immune response that cannot be measured by antibody tests. Research has found:
      • ~20% of COVID-19 patients recovered without a detectable antibody titer
      • 13% of symptomatic patients and 40% of asymptomatic patients become negative for antibodies within 8 weeks.
      • There is a robust and specific T cell response in most patients who make little or no antibodies.
      • T cell responses can be detected >100 days after symptom onset.
  • The clinical significance of T cell response is currently unknown, proof of immunity is not clear.
  • Tests to assess T cell response is currently not available for consumer use.
  • There is always a small possibility of a false positive COVID-19 test result.
My BAU value was not zero, but it was below the threshold for having antibodies. How is this possible?
  • Having a low BAU value does not specifically mean antibodies to the SARS-CoV-2 virus are present in your blood; it could be part of an immune response to other infections in the body or molecular memory.
  • To conclusively determine specific antibodies to the SARS-CoV-2 virus are present, this threshold must be met in the sample to account for the sensitivity and specificity of the test.
I tested positive for spike antibodies, but negative for nucleocapsid antibodies. Why is that?

Antibodies against the spike (S) protein are produced by your body after either an infection with the SARS-CoV-2 virus or vaccination. In contrast, antibodies against the nucleocapsid (N) protein are only produced if you had a SARS-CoV-2 infection in recent weeks. Therefore, it is entirely possible to test positive for antibodies against the S protein and negative for anti-N protein antibodies if you did not recently have a SARS-CoV-2 infection, but were vaccinated or infected at some point in the past.

Can this test measure antibodies to COVID-19 variants?
  • Yes: these variants are not known to change the performance of the test.
  • Usually, individual amino acid changes of an antigen do not affect the binding properties of the antibodies- usually only a single epitope is affected.
  • Since proteins have a large number of epitopes, the failure of a single binding point should not affect test results.
Is it possible to know whether antibodies are from a natural infection or vaccination from this test?
  • No: tests based on the spike protein and receptor binding domain cannot differentiate between antibodies generated from vaccination or natural infection. However, the test for antibodies against the N protein can indicate whether an individual has had a recent infection or not.
What is the reference standard or units the test results are based on?
  • The EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA  was found to have excellent correlation to the WHO reference standard for NIBSC Working Standard Anti-SARS-CoV-2 Antibody Diagnostic Calibrate.
  • Based on this standard, results can be indicated in Binding Antibody Units (BAU/ml) for the S protein and in a ratio for the N protein.
What are the advantages of implementing SARS-CoV-2 antibody testing at the population level?
  • Allows longitudinal information on the immune response following vaccine and natural infection to be monitored.
  • Helps understand long-term immunity: what levels of antibodies confer immunity and for how long?
  • Can be used to determine the degree of herd immunity and assess immunization efficacy.
What are the advantages of a SARS-CoV-2 antibody test for personal use?
  • Knowing if adequate antibodies have been produced after an infection or vaccination.
  • Insight into personal immune status over time in the months/years following infection/vaccination.
  • Peace of mind as normal life and activities begin to resume.
When should I measure my antibodies?
  • Your body needs time to produce antibodies after a natural infection as well as after vaccination.
  • Testing can be performed ~14 days after vaccination or 14 days after onset of COVID-19 symptoms.
What does this test measure?
  • The EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA measures the concentration of IgG antibodies at 1) the S1 domain of the spike protein, including the receptor binding domain (RBD) and 2) the nucleocapsid protein.
  • This test offers quantitative results with high sensitivity and specificity, meaning it is capable of determining the numerical value of antibodies in a blood sample.
  • This is an advancement from previously available antibody tests, which were only able to offer qualitative results regarding the presence of antibodies (yes/no)
What antibodies are produced following a COVID-19 infection?
  • Antibodies are produced as a part of the adaptive immune response.
  • Three types of antibodies are produced after infection with SARS-CoV-2: IgA, IgM, and IgG.
    • The IgM antibody response been observed in much lower levels than IgA and decreases faster following infection.
    • After several days of infection, specific IgG antibodies are produced. IgG is the most crucial antibody as it lasts longer than other antibodies, conferring potential long term immunity.
    • Scientists are still trying to understand in what capacity and for how long IgG antibodies offer immunity.