Vanliga frågor och svar
Ett antigentest för nya koronavirus påvisar själva viruset genom de specifika spikproteinerna (dvs. antigener) på dess yta för att identifiera förekomsten av viruset i provet.

An Antibody test is to detect the molecules (i.e. antibodies) that people produce after being infected with the virus. Antibodies may take several days to produce after infection and usually remain in the blood for a period after the patient recovers. There are two types, IgM Antibodies which are produced initially to fight the infection, but which disappear after several weeks, and IgG Antibodies which are produced later in the cycle and which generally remain in the body much longer. Therefore, whilst the antibody test has very limited use in the diagnosis of a new COVID-19 infection, it is essential to indicate potential immunity. However, at present, it unknown how long such immunity may subsist.

Ett antigentest baseras på en immunreaktion, medan nukleinsyretestet baseras på genetisk information. Därför kan ett antigentest gå mycket snabbare än nukleinsyretestet (15 minuter jämfört med 4 timmar). Priset för hastigheten är känsligheten. Det vill säga, ett antigentest är inte lika känsligt som ett nukleinsyretest. Nukleinsyretestet kan påvisa en mikroskopisk mängd SARS-CoV-2-virus på grund av dess känslighet vid användning av förstärkning av virusgenetisk information. Därför tar ett PCR-test flera timmar och kan orsaka förorening via aerosolbildning.

Det kräver inte laboratoriebehandling och är därför lämplig för storskalig allmän screening av befolkningen. I Nordamerika och Europa krävs att alla licensierade snabbtestantigen-produkter endast används av utbildad sjukvårdspersonal. Men det verkar troligt att antigentester för hemmabruk utan överinseende av sjukvårdspersonal kommer att tillåtas. Men om den mänskliga kroppen endast innehåller en mycket liten virusmängd, utan uppenbara kliniska symptom, kommer ett antigentest troligen att ge ett negativt resultat, och därför ett falskt negativt svar. Lyckligtvis är förmågan hos personer med en liten virusmängd att sprida viruset på motsvarande sätt lägre än hos kraftigt infekterade patienter. Antigentestet är lämpligt som ett triage- eller screeningtest för att avgöra om ett långsamt men korrekt nukleidsyretest bör erhållas. Ett antigentest kommer att vara effektivt när det gäller att snabbt identifiera personer med höga infektionsnivåer, de som mest sannolikt kommer att infektera andra, och urskilja dessa från andra med, till exempel, säsongsinfluensa. Därför kan antigentester vara effektiva när det gäller att hjälpa till att begränsa spridningen av pandemin, genom att identifiera de som mest sannolikt kommer sprida sjukdomen och isolera dem från andra. In North America & Europe all licensed Rapid-test Antigen products are currently required to only be used by qualified professionals. However, it appears likely that Antigen tests for home use, without professional supervision, will eventually be permitted.However, if the human body contains only a very low viral load, with no obvious clinical symptoms, then an Antigen test is likely to give a negative result, thus a false negative. Helpfully, the ability of people with a low viral load to spread the virus is correspondingly lower than heavily infected patients. The Antigen test is suitable as a triaging or screening test to determine whether or not a slow but accurate nucleic acid test should be obtained.An Antigen test will be efficient in quickly identifying people with high levels of infection, those who are most likely to infect others, and distinguishing those people from others with, for example, seasonal influenza. Therefore, Antigen tests can be effective in helping to limit the spread of the pandemic, by identifying those who are most likely to spread the disease and isolating them from others.

As an Antigen test detects the virus itself sample collection is very important because the virus is only present in some areas of the body. This is different from the collection of a blood sample for an Antibody test when we may expect the Antibodies to be present throughout the patient’s venous blood, although likely to be less present in capillary blood. Accordingly, we recommend the use of a sputum sample, because sputum is a secretion from the respiratory tract where the SARS-CoV-2 virus clusters the most.Hence using sputum provides a more certain method of successfully collecting a reasonable quantity of the virus in the sample, if it is present when compared with the back of the throat nasopharyngeal sample. Because the virus is unevenly distributed on the nasopharyngeal mucosa, it is not certain that a successful sample will be obtained from this area which may lead to a false-negative result. It is much more difficult and requires both expertise and some luck to obtain a truly representative sample from the back of the throat. Therefore, the nasopharyngeal sample accuracy will be lower than that of sputum. Studies have shown that after people are infected, the viruses survive, and thus can be detected, in the digestive tract, especially in the intestinal stool. Therefore, if convenient (e.g. in the hospital or at home), a stool sample is another option for testing; Saliva samples mixed with sputum also have a certain probability of detection, although the amount of virus contained is lower than pure sputum.

Sputum is the mucus that is coughed up from the lower airways (the trachea and bronchi). When taking a sample one should avoid its contamination / dilution with saliva so far as possible. Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth.

The WHO has always been a supporter of Antigen testing. Experts point out that compared with conducting an accurate test every two weeks, conducting a relatively insensitive quick test twice a week can more effectively contain the spread of SARS-CoV-2. The reason is that it is more helpful in containing the spread of the infection where the focus is on identifying those who are likely to spread SARS-CoV-2, rather than locating anyone who is infected in any way with SARS-CoV-2 – but with a low infection much less likely to spread it.

Den första LÄTT ATT ANVÄNDA COVID-19-test är nu CE-certifierade och godkända för distribution och försäljning i hela Europa.

The HealthOx Biotech Ltd Antigen and Antibody tests are certified in the UK, Europe and Asia, and ready for medical use. They are approved by the MHRA and BSI and have earned the UK’s British Standards Institution (BSI) mark and the EU’s CE Certificate of Compliance.

All of our test kits can be ordered online via our website for delivery within 2-5 days. We also cater for telephone orders. Please contact support@healthoxbiotech.com