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How sensitive is the KnowNowᵀᴹ Test?

What’s important when it comes to sensitivity is how much virus needs to be present in the patient sample for the test to give a positive signal. This is known as the 'Limit of Detection', and we measure this rather than clinical sensitivity as it is much more informative.

Our Limit of Detection is between 50,000 and 200,000 viral copies per mL, making our test more sensitive than other rapid antigen tests available. The Abbott BinaxNow test, for example, needs 1,000,000 viral copies per mL in order to get a positive signal.

The KnowNowᵀᴹ Test's low Limit of Detection means it can detect infected people as early as day 3 to 4 of infection. This is before they become highly infectious, and a day or two earlier than most tests available (based on models of viral load in disease progression).

If you'd like to read more about this subject, we recommend reading this paper. It argues that the "Limit of Detection matters and directly impacts efforts to identify, control, and contain outbreaks during this pandemic" since "higher LoD are likely to miss nonnegligible fractions of infected individuals." It also makes the case that Limit of Detection values for tests using universal standard metrics should be readily available in the public domain to enable like-for-like comparison.

How much space do I need to store the tests?

One box contains 25 tests, and measures 20cm (L) x 21cm (W) x 8cm (H).

The space required depends on how many tests you require at any given time. However, as the KnowNowᵀᴹ Tests can be stored at any temperature between 2 and 30 degrees, special storage facilities should not be required in the UK, unless there is unusually hot weather.

How long will it take a qualified clinician to administer each test?

From our own studies with partners, we estimate that a clinical professional can administer one test every 3.5 to 4 minutes. This assumes that they collect saliva samples from individuals, set the KnowNowᵀᴹ Test devices aside to develop for 15 minutes, and collect samples from further individuals before reading the results from earlier tests.

Are you taking shortcuts or risks by developing the KnowNowᵀᴹ Test so quickly?

No, we're not taking any shortcuts or risks. The KnowNowᵀᴹ test has been precisely developed, rigorously tested, and approved by the necessary bodies.

As with COVID vaccine development, the speed at which we’ve been able to move has been accelerated by the enhanced support and focus afforded to the sector by all stakeholders, such as the government, the pharmaceuticals industry, academic institutions and so on.

We have conducted two clinical studies. The first was a UK Government-based study across ten UK hospitals; the second was with Liverpool School of Tropical Medicine. We have also carried out our own analytical assessments, as well as two Public Health England analytical assessments.

The KnowNowᵀᴹ Test has been CE marked for professional use within a healthcare context and is approved by the UK's Medicines and Healthcare products Regulatory Agency (MHRA).

What is SARS-CoV-2?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the name given by the International Committee on Taxonomy of Viruses (ICTV) to the virus responsible for causing the disease, COVID-19.

Who is Vatic?

Vatic is a predictive health company focused on making medicine more proactive. We deliver on-the-spot tests which detect subtle biomarkers in people’s bodies to predict illness before it becomes acute or infectious.

Our first product is KnowNowᵀᴹ, a rapid turnaround COVID-19 antigen test, that is designed to identify COVID-positive people before they become highly infectious*, based on just a small saliva sample.

How frequently should employees or visitors be tested?

We recommend that individuals are tested as regularly as possible to keep workplaces, venues and communities safe.

It is important to remember that individuals can still go on to be exposed to the virus following a negative test result. Additionally, a high proportion of infectious people show no symptoms at all, and so regular testing is key to breaking the chain of transmission.

Depending on the scenario, we would recommend that testing is performed every 2-3 days, or daily, depending on the scenario.

Is there a limit to how frequently I can take your tests?

No, there's no limit at all. KnowNow is specifically designed for frequent testing in order to offer the best chance of identifying infectious individuals as early as possible.

We recommend that individuals are tested as regularly as possible to keep workplaces and communities safe. Depending on the scenario, we would recommend that testing is performed every 2-3 days, or even daily, depending on the scenario.

What is the limit of detection of the KnowNowᵀᴹ Test?

The Limit of Detection (LoD) is the smallest amount of virus in a sample that a given device can consistently detect.

The Liverpool School of Tropical Medicine carried out an analytical study of the KnowNowᵀᴹ test, which determined that the LoD is 500 plaque-forming units per millilitre (PFU/ml). Based on accepted models of viral load in disease progression, this very low LoD suggests that the KnowNow test can detect infected people as early as day 3 to 4 of infection. This is before they become highly infectious, and a day or two earlier than most tests available.

In the absence of a single study that compares the LoD of KnowNowᵀᴹ to that of other tests, it is not possible to do a like-for-like comparison of the LoDs of different lateral flow tests determined by different studies. This is because there wouldn't be parity across cell cultures and strains of the virus used in the different studies. Additionally, it's important to consider that what the KnowNowᵀᴹ test detects is fundamentally different from other tests. KnowNowᵀᴹ is a true infectivity test which looks exclusively for the spike protein only present on active SARS-CoV-2 viruses. Whereas other lateral flow tests detect the nucleocapsid protein encapsulated in the centre of the virus, which can be present whether the virus is active or not.

The PFU/ml measure, as used in the Liverpool School of Tropical Medicine KnowNowᵀᴹ analytical study, is a measure of only the number of virus particles capable of forming plaques in a given sample - viral particles that are defective or which fail to infect their target cell will not produce a plaque and so are not counted by this measure. No inference can be made about the relationship of PFU to the overall number of viral particles in the sample, since this will differ from sample to sample.

Since the KnowNow test specifically detects infectious viral particles only, an LoD measured in PFU/ml is an informative and appropriate measure. However, for other lateral flow tests which indiscriminately detect active and inactive viral particles, an LoD referencing PFU/ml is not particularly informative or comparable to the KnowNowᵀᴹ LoD. For example, the sample used to determine LoD may have had a very low PFU/ml, but many inactive viral particles which were detected by the test. Ultimately, other lateral flow tests are not true tests for COVID infectivity, they do not detect only infectious virus like the KnowNowᵀᴹ test does.

If you'd like to read more about this subject, we recommend reading this paper. It argues that the "Limit of Detection matters and directly impacts efforts to identify, control, and contain outbreaks during this pandemic" since "higher LoD are likely to miss nonnegligible fractions of infected individuals." It also makes the case that LoD values for tests should be benchmarked against a universal standard and readily available in the public domain to enable like-for-like comparison of SARS-CoV-2 detection methods.

When did you start?

Vatic was founded in October 2019 by Alex Sheppard and Dr. Mona Kab Omir.

When the first wave of COVID-19 started in the UK in early 2020, our team immediately saw an opportunity to contribute to global efforts to tackle the pandemic, and leveraged work already underway on antigen testing to quickly start developing the KnowNowᵀᴹ Test.

Where do you make your KnowNowᵀᴹ tests?

KnowNowᵀᴹ Tests have been invented, developed and manufactured in the UK.

Had COVID - 19 symptoms in the last 2 days? Apply here to help us make testing accessible to all.