COVID-19 test accuracy is typically determined by ‘specificity’ and ‘sensitivity’.
Specificity is about the extent to which you can eliminate false positives; sensitivity is how much virus needs to be present before a test picks it up. So there is always a need to strike a balance, when testing, between trying to pick up the virus as early as possible, versus accidentally delivering a positive test result for someone who is not actually infected.
The specificity of the KnowNowᵀᴹ Test is 99.9%. In more than 300 negative patient saliva samples, we haven’t had a single false positive.
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 very 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 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.
There are just 4 simple steps to the KnowNowᵀᴹ Test.
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.
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.
The KnowNowᵀᴹ test will provide a result within 17-18 minutes of an individual arriving for their test.
The process of taking the saliva sample, mixing it with the buffer solution and dropping it onto the KnowNow test device should take a clinical professional no more than 2 to 3 minutes.
It then takes just 15 minutes for the test result to develop in the KnowNow device test results window.
The test result should not be read and interpreted after 60 minutes. If it wasn't possible to read and interpret the results between 15 and 60 minutes after dropping the solution into the sample well, the test should be discarded and the process repeated with another new test and saliva sample.
The mechanism underpinning the KnowNowᵀᴹ test mimics the means through which the virus interacts with the surface of a human cell in order to detect it. As a result, we expect that it will continue to identify the SARS-CoV-2 virus even in the face of further potential mutation in the future, unlike tests based on antibodies.
We have modelled the difference between the Wuhan and 501Y mutations in a recombinant protein model to give us initial analytical evidence that the KnowNow test reacts to these variations of concern. And we are currently carrying out a study on live samples of these and other mutations to gather practical evidence of this.
In fact, we predict that the KnowNowᵀᴹ test may potentially become even more sensitive as the virus mutates to become more infectious. And we will continue to carry out further analyses and studies to support this prediction, and confirm that KnowNow continues to function on newer mutations as they arise.
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.
So that we adhere to the strict rules around lateral flow tests, we have to make sure that anyone activating a sample pack is doing so purely to learn more about KnowNow Testing, and not as means of administering a clinical test.
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.
The expiry date of KnowNowᵀᴹ Tests will be clearly marked on their packaging, and you can expect the shelf-life of each box of tests to be at least four months.
There have been questions raised around the sensitivity of rapid lateral flow antigen testing for SARS-CoV-2 as compared to PCR testing. However, these questions have been strongly challenged by the scientific community.
PCR tests identify the presence of the SARS-CoV-2 virus in the body, regardless of whether the virus is actively infectious. The PCR testing process amplifies the genetic code of the virus so that even minuscule amounts of the virus in the sample can be picked up. This makes for a powerful test, but since viral fragments can linger in the body for weeks even after the infection has cleared, infected individuals being tested using PCR will show as positive for a median period of 22–33 days in total. On the other hand, most people infected with SARS-CoV-2 are contagious only for 4–8 days.
So whilst PCR testing for SARS-CoV-2 may have been considered the "gold standard" test up until now, it will by definition show different results when compared to lateral flow tests which aim to identify individuals based on viral loads which suggest they are within their infectious window. This discrepancy between what each test is actually testing for has caused some issues where PCR testing has been used to evaluate the effectiveness of lateral flow tests, such as in the mass testing rolled out in Liverpool in November 2020.
The KnowNowᵀᴹ Test goes a step beyond other lateral flow tests with its unique, patented detection mechanism which only shows a positive result when live infectious virus is identified in the sample. As a result, PCR tests will similarly show different results to the KnowNowᵀᴹ Test in certain cases, since they will show positive results even for individuals outside of their infectious period.
For a much more comprehensive and referenced answer, you may like to read "Clarifying the evidence on SARS-CoV-2 antigen rapid tests in public health responses to COVID-19" from the Lancet.