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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 is a KnowNowᵀᴹ Test administered?

There are just 4 simple steps to the KnowNowᵀᴹ Test.

  1. Swab the mouth: The KnowNowᵀᴹ Test requires just a saliva sample to be taken easily and comfortably from the mouth. We know how uncomfortable and painful other lateral flow antigen tests or polymerase chain reaction (PCR) tests can be, with swabs going high into nostrils and all the way back to tonsils. It was really important to us that people would feel happy to take a KnowNow test on a regular basis.
  2. Shake the tube: The saliva swab is placed into a buffer solution in a small tube, and shaken up to mix it well.
  3. Squeeze on panel: A few drops of the mixed solution is squeezed onto the KnowNowᵀᴹ Test device.
  4. Know in 15 minutes: It takes just 15 minutes for the positive or negative result to appear in the test result window on the KnowNowᵀᴹ Test device. No need to wait 24-48 hours for results, as you would with a PCR test.

How does KnowNowᵀᴹ compare to COVID-19 PCR tests?

KnowNowᵀᴹ offers two key benefits over polymerase chain reaction (PCR) tests.

The first benefit is that the KnowNowᵀᴹ test needs only a saliva sample, which can be taken easily and comfortably from the mouth. PCR tests usually need a nasopharyngeal, anterior nasal or tonsil sample, all of which are painful and unpleasant for the individual being tested and more challenging to collect effectively for the clinical professional administering the test. No one wants to be made to cry or gag, or make someone else cry or gag, on a regular basis!

The second benefit is that the KnowNow test uses its unique detection mechanism to determine whether an individual is actually infectious, whereas PCR tests identify whether SARS-CoV-2 viral matter is present in an individual's body, regardless of whether it is already inactive.

Although PCR tests have been seen as the "gold standard" test for the SARS-CoV-2 virus, they do have a number of drawbacks. Laboratory processing is required, meaning that there is a delay before results can be returned, and the associated costs are relatively high. Also the detection mechanism does not specifically identify whether individuals are infectious. In fact, PCR tests detect the virus long after the infectious period, and individuals can continue to test positive for a mean of 17 days after they have stopped being able to infect others (source). This means that people who are not infectious are unnecessarily quarantined as a result of a positive PCR test.

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 specific is the KnowNowᵀᴹ Test?

The KnowNowᵀᴹ Test's specificity is 100%. In more than 700 negative patient saliva samples, it hasn’t returned a single false positive result.

This is so important for getting life back to normal. We don't want anyone to be stopped from going to work, heading off on holiday or socialising at events, when actually it would be perfectly safe for them to do these things.

Specificity is particularly important when disease prevalence is low and tests are intended to be used at enormous scale. For example, if a test with just a 3% false positive rate is used on one million people per day, that would result in 30,000 people per day being falsely identified as infectious with COVID-19 and being unnecessarily asked to self-isolate.

Why test people who don't have symptoms?

SARS-CoV-2 is able to spread from individuals who are pre-symptomatic or asymptomatic. As a result, testing and isolation based on symptoms alone will not be sufficient to stop the spread.

This narrative review of 16 clinical studies around the globe concludes that between 40-45% of those infected with SARS-CoV-2 never develop symptoms, and that these asymptomatic carriers can infect others for an extended period, perhaps longer than 14 days.

Regular community testing with a rapid antigen test like the KnowNowᵀᴹ Test to identify asymptomatic, but infectious, individuals offers one way to break the chain of transmission and enable the re-opening of societies.

How do I order tests?

We're so pleased that you'd like to order our KnowNowᵀᴹ Tests. At the moment we are running some pilots with a few key partners, before distributing our tests more widely.

Please fill in our form and our team will get back to you.

What is a lateral flow test?

A lateral flow test is a simple diagnostic device designed to detect the presence or absence of a target substance in a liquid sample without the need for specialised and costly equipment.

The most commonly recognised type of lateral flow rapid test strip is the pregnancy test.

Who makes the KnowNow Test?

The KnowNowᵀᴹ Test has been invented, developed and manufactured in the UK by Senseutics Limited, trading as Vatic.

How should used KnowNowᵀᴹ Tests be disposed of?

Used tests, swabs and buffer dropper tubes should be disposed of as potentially hazardous clinical waste.

What is a KnowNowᵀᴹ Test?

The KnowNowᵀᴹ Test is the UK's only on-the-spot COVID-19 test that uses just your saliva to tell you if you are currently able to infect someone else with COVID-19.

Unlike other tests, the KnowNowᵀᴹ Test won't give you a positive result if you have been exposed to the SARS-CoV-2 virus in the past, but are no longer able to infect other people.

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