Corona Rapid Tests are intended to supplement the limited resources available to contain the corona pandemic with a fast, inexpensive and decentralized screening method. These are not designed to replace the PCR test, but to complement it.
The advice from certain medical circles that an antibody and/or rapid antigen test alone is not sufficient to rule out a suspected case 100% is correct. But this also applies to any other analytical method, including the PCR test, which is of course important as a detection method. As the sole method, however, the PCR test quickly reaches its capacity (laboratory equipment, can only be used centrally) and economic limits (costs) worldwide, with which our health system is increasingly confronted due to the development of the rapidly increasing number of infections.
The proteins of the immune system that bind to the anitgens of foreign substances are called immunoglobulins (Ig) or antibodies. They are manufactured to fight pathogens such as bacteria, viruses and parasites. The main function of Ig is to facilitate the destruction of foreign pathogens. IgG and IgM are two classes of immunoglobulins. The main difference between IgG and IgM is the IgG’s late reaction to a disease, while IgM is produced immediately after exposure to a particula antigen. IgGs can be found throughout the body, mainly in bodily fluids, while IgMs are found in blood and lymph. IgGs provide a long-term response to a particular antigen and provide lasting immunity. IgMs, however, show a short-term reaction.
The available resources/capacities for molecular biological mass tests, in our opinion, will not be sufficient in the future. There are not enough laboratory diagnostic devices available, the swab materials and accessories can run out (see history of disinfectants and respiratory masks) and qualified specialists are often not available enough, e.g. sick themselves. Laboratories are currently often overloaded.
Corona Anti-gene and Anti-body One Step Rapid Tests can be carried out inexpensively, decentrally and by any medical specialist. The quick test sets are fully equipped. No further laboratory equipment is required. Results are available within 10–15 minutes after the test.
Since there is currently no specific therapy or vaccination, anti-body and anti-gene rapid tests are primarily used as a screening method, to answer epidemiological questions and for hygiene management, and not as a basis for therapy decisions. A possibly slightly lower specificity compared to the PCR test can thus be easily accepted here. In addition, one can also recognize asymptomatic carriers, i.e. people who can infect other people, but are symptom-free themselves.
It is also very important for our daily work to know which patient or employee is already asymptomatic. This is of great concern with COVID-19, as asymptomatic carriers play a huge role in the spread of the virus.
The question of an existing immunity after a possible infection is also of great relevance, namely when it has to be decided which employees (e.g. doctor, nursing staff) can currently look after infectious Covid-19 patients.
Antibodies can be detected after about 7–10 days of infection, which is why the Corona rapid test relies on the combination of IgG and IgM detection. The course of antibody formation over time is clearly shown on this homepage and provides you with actual information that can support you and your patients.
The question of detectability of antibodies over time is secondary in view of the incubation time and phase of slowly increasing symptoms lasting around 7–10 days. It can be assumed that a significant proportion of patients will only present after a few days and will then already have detectable IgM.
A PCR test would usually also take place only after the onset of symptoms.
If you have a positive test result, it is likely that you may have had COVID-19 and might have developed an antibody response to the virus. There is a small chance that this test can give a positive result that is wrong (a false positive result).
A negative test result means that the antibodies to the virus that causes COVID-19 were not found in your sample. However, it is possible for the test to give a negative result that is incorrect (false negative) in some people with COVID-19. A negative result may occur if you are tested early in your illness and your body hasn’t had time to produce antibodies to infection. This means that you could possibly still have COVID-19 even though the test is negative.
The Covid-19 Antigen Test is an immunochromatographic test and checks for protein components of the Sars-Cov‑2 pathogen.
It is a lateral flow assay:
The test cassette contains a conjugate pad with colloidal gold and a membrane strip on the test line that is precoated with antibodies against the Sars-Cov‑2 antigen.
If Sars-Cov‑2 antigen is detected in the sample, a black line appears because an antibody-antigen-antibody-gold conjugate complex is formed.
The rapid antigen test presented on this page has a sensitivity of 92% and a specificity of 98%. The antigen test shown on this homepage closes the so-called diagnostic gap to the antibody rapid test.
The diagnostic gap, also known as the diagnostic window, in medicine, refers to the period that elapses between infection and the time from which the previous or current presence of a pathogen in an organism can be reliably detected by a specific test.
The rapid antigen test is carried out with a nasal swab and checks for protein components of the Sars-Cov‑2 pathogen; put simply, the antigens bind the in the nasopharynx existing virus and make it visible and measurable. It works just as quickly as an antibody test: the test result is available within 15 minutes with reliable accuracy (sensitivity: 92%, specificity: 98%). This test procedure can therefore also be used in the initial phase of a potential illness and in suspected cases, even if no recognizable symptoms are displayed.
The sensitivity of a diagnostic test procedure indicates the percentage of sick patients in which the respective disease is actually recognized by the application of the test, i.e. a positive test result occurs. It is defined as the quotient of true positive test results and the sum of true positive and false negative test results.The higher the sensitivity of a test, the more reliably it detects the disease. A negative result in a test with high sensitivity can rule out the disease you are looking for with a high degree of probability.
The specificity of a diagnostic test procedure indicates the probability that actually healthy people who do not suffer from the disease in question will also be recognized as healthy in the test. It is defined as the quotient of true negative test results and the sum of false positive and true negative test results — i.e. all test results that were actually not based on any disease.The calculation is based on (SPE = specificity):
- SPE = correctly recognized as healthy / all healthy
Antigens are foreign proteins against which the immune system forms antibodies. It is not a gene in the traditional sense. The word ‘antigen’ is not derived from ‘genetics’, but from the English -
‘antibody generating’ (= producing antibodies).