What Are Antigen-Detecting Rapid Diagnostic Or Lateral Flow Tests?
Antigen-Detecting Rapid Diagnostic Tests use lateral flow immunoassays to detect SARS-CoV-2 viral proteins (antigens) in swabs from the nose, or both throat and nose, to offer a faster and less expensive method to detect SAR-CoV-2 than PCR tests. The tests give a quick result, often between 15-30 minutes, using a disposable test cassette that is similar to some pregnancy tests.
The World Health Organization’s performance standards require that such tests correctly identify at least 80% of infected people (test sensitivity) and correctly identify the infection cause to be SARS-CoV-2 in 97% of cases (test specificity). In the Cayman Islands, by Regulations, only LFTs that meet these standards can be imported or supplied.
What Are Some Key Benefits Of Lateral Flow Tests?
Some of the key benefits that the Government expects to receive are as follows:
- They are 10% or less of the cost of a PCR test;
- They can be used and interpreted by someone who has no prior expertise, and many are designed for home use;
- People can conduct the tests at home or at the workplace, so travel to and mixing with people in a healthcare setting is not required;
- They are self-empowering which many members of the public will be grateful for (e.g. in the protection of the elderly and vulnerable);
- They can assist in identifying people who are infected but asymptomatic in a matter of minutes;
- Their use can decrease the workload on laboratory services;
- They greatly increase access to a reliable diagnostic technique; and,
- Their use can decrease disruptions within educational, caregiving and employment settings.
What Are Some Key Limitations Of Lateral Flow Tests?
Although LFTs do not tend to perform as well as the more sensitive PCR tests when viral loads are low, they do perform well with higher viral loads (when someone is most infectious) or when used repeatedly.
All testing for SAR-CoV-2, including lateral flow testing, depends on the integrity of the sampling technique and therefore the sample. Care must be taken to an avoid improper or insufficient collections (e.g. swabbing the nostril too quickly). The manufacturer’s instructions must be followed carefully in order to ensure the accurate results.
What Is The National LFT Policy For?
The purpose of the policy is to provide a framework and guidance for the strategic use of lateral flow tests, both for home and supervised use, in order to:
- ensure the tests used by the Government, private sector and home use are accurate and reliable;
- reduce the threat of SARS-CoV-2 infections with the early detection and isolation of any positive person which will have an immediate impact on the numbers who might present to clinics and hospitals;
- achieve more rapid and widespread testing capacity in the Cayman Islands;
- enhance our ability to protect some of our most vulnerable populations, including our children in our early childhood care and education centres and schools, who are not yet eligible for an approved COVID-19 vaccination;
- provide additional information to guide the Government’s policies, from the collection and reporting of testing results; and
- build confidence that places of work and recreation can be safe environments even in the face of community transmission, and that attending or patronising such places does not create unreasonable risks to a person’s health or the health of family members with whom they live.
Additionally, this National policy also serves as the overarching framework for various sectors (e.g. education, tourism, social care services, etc) to create guidance documents that will assist with the deployment of lLFTs in their respective organisation or setting. Private sector employers may also use this policy to assist in developing their own lateral flow testing policies as this document outlines the reporting requirements and other recommendations such as testing intervals.
What Lateral Flow Tests Can I Use?
Only LFTs that meet the criteria set out in the Control of COVID-19 (Testing) Regulations, 2021, should be supplied for the purpose of SARS-CoV-2 rapid testing in the Cayman Islands (including tests used in workplaces or homes for personal use).
The UK Health Security Agency (formerly known as Public Health England) has undertaken rigorous testing for a large number of lateral flow devices and this is set out here.
Three LFTs brands have been initially identified for use by the Health Services Authority and were selected based on recommendations and proven outcomes as noted by the regulatory bodies at World Health Organization (WHO) and the UK Health Security Agency (formerly known as Public Health England). These three are:
- ACON Biotech Flowflex SARS-CoV-2 Antigen Rapid Test
- Bioperfectus Technologies Novel Corona Virus Ag Rapid Test kit, and
- Hughes Veritas Rapid Antigen Test for SARS-CoV-2.
Any other LFT brand selected for use by the Cayman Islands Government will undergo confirmatory testing by the accredited laboratory of the Cayman Islands Health Services Authority (HSA).
On the 26th of November 2021, the Medical Officer of Health, under regulations 4(3) of the Control of COVID-19 (Testing) Regulations, 2021, has also approved the use of FlowFlex SARS-CoV-2 Antigen Rapid Test kits marked 'For professional in vitro diagnostic use only' for personal use provided that:
- They are individually packaged for distribution in appropriate bags. These same bags can be used for placing the testing material after testing for disposal.
- It is also recommended that clear instructions be provided to users of these test kits.
Who Can Be Screened Using Lateral Flow Tests?
In order to prevent additional spread of the virus, screening is intended to identify persons with SARS-CoV-2 infection who have either no symptoms or mild symptoms (sometimes termed ‘paucisymptomatic’) and who might otherwise go undetected.
Screening is not intended for children under the age of 2 years.
Screening is not intended for persons who are symptomatic. In line with Public Health advice, persons with symptoms should stay home when sick. Any person with symptoms suggestive of COVID-19 disease should contact their local healthcare provider or the Flu Hotline to seek advice on the best next steps. The Flu Hotline can be reached on 1-800-534-8600 or 947-3077 (Digicel), or email firstname.lastname@example.org.
Screening is not intended for persons who have recovered from laboratory confirmed (PCR) COVID-19 test within the past 90 days and are asymptomatic. To avoid false positives, they should follow the advice of the Public Health Department on how to conduct future testing (including screening tests).
Who Can Use Lateral Flow Tests?
The Cayman Islands Government recommends the use of approved LFTs for a wide range of purposes and contexts, including the following:
- For testing at home, as part of a personal routine to safeguard the health and safety of individuals and their families.
- Under the direction of Public Health for diagnostic purposes, as part of an outbreak investigation and response, in order to:
For routine testing for some healthcare workers and other frontline workers.
For high risk congregate settings that house some of our most vulnerable populations (e.g. schools, institutional homes, prisons and detention centres).
For organisations providing high touch and personal services to the public (e.g. barbershops, hairdressing salons, and spas), social venues (e.g. restaurants, bars, nightclubs, and cinemas), and fitness facilities (e.g. gyms, fitness centres, or other indoor fitness areas).
As part of a voluntary or mandatory testing programme by employers, especially within organisations with high volumes of customer traffic, in order to ensure that workplaces operate as safely as possible and can maintain business continuity.
With sports athletes and staff engaging in moderate and high risk sports organised by sports leagues, including youth sports teams and activities.
Visitors, prior to entry into certain settings, including but not limited to healthcare facilities and institutional care homes; prisons and places of detention; and as may be required by certain businesses and venues.
- provide a more rapid response for identifying persons actively infected with SARS-CoV-2 virus to help guide clinical and infection control decisions; and
- reduce the number of children and families required to isolate as a result of a positive case.
How Will The Costs Of Implementing A Screening Testing Programme Be Met?
All test kits for screening testing using LFTs within the civil service will be met by the Government and will be provided free of charge to employees.
All test kits for screening and surveillance testing using LFTs for staff, teachers and children in ECCE centres and schools, both Government and private, will be provided by the Government and will be free of charge to staff, teachers, and children. Supplies of test kits will initially be provided to staff, teachers, and children for routine screening and, in the event of an outbreak or a positive case, additional supplies will be provided for those individuals only.
In any other scenario, the full cost of implementing a screening regime using LFTs, including the purchase of LFT kits, must be borne by the employer, organisation, or individual.
When Lateral Flow Tests May Be Administered By Public Health?
LFTs may be used by PH for diagnostic purposes, as part of an outbreak investigation and response. Where LFTs are used by PH for this purpose the tests will be administered to affected children and adults, regardless of vaccination status and these LFTs will form part of a PH strategy to:
- Provide a more rapid response for identifying persons actively infected with SARS-CoV-2 virus, to help guide clinical and infection control decisions.
- Reduce the number of children and families required to isolate as a result of a positive case.