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How have you validated the accuracy of your tests?

To date we have conducted three clinical studies. The first was a UK Government-supported National Institute for Health Research (NIHR) study across ten UK hospitals; the second was with Liverpool School of Tropical Medicine, and the third is a community study that we have led ourselves. We have also carried out our own analytical assessments, as well as two Public Health England analytical assessments.

We have worked with over 280 negative patient samples and around 100 COVID-19 positive patients across our studies. We are also currently carrying out a 650+ patient clinical trial with sites in the UK, USA and Brazil to provide us with a higher volume of clinical data, and with a view to additional regulatory approvals to widen the reach of the impact we can have globally in pandemic recovery.

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.

How long can unused KnowNowᵀᴹ Tests be kept before they expire?

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.

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.

Where do you make your KnowNowᵀᴹ tests?

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

Why does the KnowNowᵀᴹ test use a saliva sample?

We chose to design our unique KnowNowᵀᴹ test for COVID-19 infectiousness to work with a simple saliva sample, so that it would be comfortable and easy to administer, and to ensure that anyone would be happy to take a test every day if required. We believe that patient comfort and happiness leads to increased participation in routine testing, and ultimately increases the probability that COVID positive patients can be detected before they've had a chance to infect others.

The focus of our first clinical study was to assess the feasibility of using saliva sampling, to refine our saliva collection method, and also to assess the overall usability of the KnowNow test. This was a UK Government-supported National Institute for Health Research (NIHR) study carried out across ten UK hospitals with 100 patients participating. Through this study we determined that saliva sampling was both effective and user-friendly, and identified a specific swab for sampling. We chose not to opt for a spit collection method for our saliva sample, as providing a spit sample can be challenging for some patients, particularly the elderly or those suffering with COVID-19 symptoms.

For other COVID-19 tests, throat and nasopharyngeal swabbing is one of the most common types of sample collection. However, a number of studies have explored various issues with these types of sample collection, including:

  • The sample collection method requires a swab to be inserted into the patient's throat and/or far into their nostril and rotated, causing discomfort to patients due to the procedure’s invasiveness, and even inducing bleeding in their tonsils and posterior pharynx. (1)
  • The discomfort or even pain of the sample collection method has a detrimental impact on compliance for serial testing, as patients are unwilling to subject themselves to the test on a regular basis. (2)
  • Nasopharyngeal sample collection presents a considerable risk to healthcare workers, because it can induce patients to sneeze or cough, expelling virus particles. (2)
  • There are several situations where nasopharyngeal swabs would cause particular harm, such as in patients with coagulopathy, those undergoing anticoagulant therapy, or those with significant nasal septum deviation. (3)
  • These tests are not always successful at the first attempt, even though performed by trained healthcare workers, and shortages of swabs and protective equipment are frequently reported. (3)
  • They show relatively poor sensitivity for SARS-CoV-2 detection in early infection and are inconsistent during serial testing. (2)

Some tests have been designed to work with anterior nasal swabs, as a somewhat less invasive alternative to nasopharyngeal swabs. However, there is some evidence to suggest that nasal swab testing produces less sensitive results and may miss patients with lower viral loads (4).

References:

(1) Exploring salivary diagnostics in COVID-19: a scoping review and research suggestions

(2) Saliva is more sensitive for SARS-CoV-2 detection in COVID-19 patients than nasopharyngeal swabs

(3) Saliva as a Candidate for COVID-19 Diagnostic Testing: A Meta-Analysis

(4) Nasal-Swab Testing Misses Patients with Low SARS-CoV-2 Viral Loads

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.

What does a positive test result look like and mean?

Positive KnowNowᵀᴹ Test result
Positive KnowNowᵀᴹ Test Result

If there is one red line visible next to the "C" in the KnowNowᵀᴹ device test results window, and any line at all, no matter how faint, appears next to the "T", then the test result is positive. This indicates that the SARS-CoV-2 antigen has been detected in the sample.

Following a positive result, current government guidance on matters including self-isolation and reporting the result should be followed.

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.

Isn't lateral flow testing less good than PCR testing?

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.

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