Covid-19 test: to whom, for what, how to apply …
Pharmacies already sell national tests – but there are questions. They didn’t give money to the State Institute … So – an express test, ELISA or PCR?
At a meeting in Kiev, Ukrainian Minister of Health Maxim Stepanov said that in Ukraine he plans in the near future to increase the number of tests for coronavirus using polymerase chain reaction (PCR) – from six thousand to eight to ten thousand a day. However, he said that already this week, the Ministry of Health of Ukraine is planning consultations on mass tests using another technology – the enzyme-linked immunosorbent assay (ELISA), which determines the presence of antibodies against the virus in the body – that is, immunity. To determine the latter, you can use the rapid tests, available free of charge today in pharmacies. The method is not the most precise, but fast. And all of these are national proposals. Thus, Ukrainians can, if they wish, ensure their health and the state – in the presence or absence of collective immunity in society. This problem, in particular, will be crucial for the removal of quarantine. Consequently, the sooner mass tests begin, the more quickly virologists will know the country’s epidemiological picture.
PCR tests: the gold standard for diagnosis, the NASU Institute is ready to produce them, but …
What is the difference between PCR tests and rapid tests, and in which cases they are used, Ukrinform has already written (see – HERE). But remember. Polymer chain reaction (PCR) tests detect the presence of the virus itself or its DNA in the human body. This method is used to test people with clinical signs and suspected Covid-19 disease. A sample of research material is taken from the mucous membrane of a person’s nose and examined exclusively in reference laboratories. Today, this is the “absolute benchmark” for determining the patient’s infection – the method provides almost 100% reliability of the results.
The sample material for the study is taken from the mucous membrane
The Ministry of Health has so far obtained PCR tests from foreign production – mainly Chinese. Although Ukraine has its own developers of these tests – both private (Diagen companies and Ukrainian Genetic Technologies) and public.
In particular, Ukrainian scientists are ready to provide the country with test systems, even now. The NASU Institute for Molecular Biology and Genetics (IMBG) has long declared that it is ready, subject to adequate funding, to produce up to 20,000 PCR systems per week. In late January 2020, on the orders of the National Security and Defense Council, scientists from the IMBG were the first in Ukraine to develop such test systems. Their certification confirmed an accuracy of 99.9%. The cost of a reaction in the Ukrainian test is 250 UAH, while foreign analogs cost between 370 and 450 UAH.
Three months have already passed and the “charrette” of public funding “is still there”. As Ukrinform was informed at the Institute, the institution has still not received money for the mass production of test systems, although negotiations with the authorities have not stopped.
“I also had a meeting with the director of the Institute for Molecular Biology and Genetics. We must be aware that it is our scientific potential that we must involve 100%, including in the manufacture of these PCR systems, but scientists are not manufacturers, so it is important to create synergies between scientists and industrial companies that can directly manufacture. This is what we have provisionally agreed with the head of the scientific institution and we look forward to continuing our cooperation, “said Minister of Health Maxim Stepanov.
… There are already private campaign production tests
In the meantime, the Ministry of Health has announced that it is sending 250,000 PCR tests from the company Ukrgentech to the regions of Ukraine.
“Indeed, the delivery of PCR systems from a Ukrainian manufacturer has already started – this is the Ukrainian genetic technology company (Ukrgentech). They completed their first delivery on April 24. A PCR system has nearly 100 tests. Two thousand PCR systems were delivered, which immediately went to the regions – this represents almost 200,000 tests. Today (April 25 – Auth.) – another thousand (PCR systems), ie 100,000 additional tests, then another 150,000 are expected, “the minister confirmed.
Delivery of PCR systems from the Ukrainian manufacturer has started
It is interesting to note that there are great doubts concerning the declared production capacities of the company Ukrgentech and its financial viability for the production of such batches of PCR systems in the professional environment. For example, the market is too narrow for a small circle of participants to be unaware of the production and resource capacities of others. And various rumors circulate about the Ukrgentekhs – the company is young, little known, with a very broad statutory activity and a statutory fund of only 1,000 UAH, not public.
Neither the company “Diogenes”, nor the Institute, nor Ukrgentech, according to Ukrinform sources, could reach such production volumes of specific test systems without appropriate orders and investments. Therefore, a logical question arises as to why “private traders” have production possibilities and orders from the state, but the state institute still does not. Okay, it’s kind of like an ordinary bureaucracy.
Rapid “pharmacy” tests: rapid but not always precise
An express test (or rapid test) determines the presence in the blood of a person not of the coronavirus itself, but of antibodies formed in the fight against it. It is now available for sale in most pharmacies. The test kit is somewhat similar in principle to the pregnancy determination test.
The detection of antibodies to the COVID-19 coronavirus is based on the immunochromatographic analysis method. The study is carried out independently, by sampling and studying the reaction of the capillary blood. A drop of blood (a study sample) should be applied to the membrane in a special window on the test cassette. In the presence of antibodies against the nCoV 2019 antigen in the sample, the latter reacts with the colored conjugate and forms a complex with anti-human IgG antibodies immobilized on the membrane (IgG test zone) and anti-IgM antibodies humans (IgM test area). The result of this reaction is the appearance of one or two colored lines in the test areas. The presence of such lines on the test part of the membrane indicates a positive result (i.e. anti-coronavirus antibodies are present in the human body), while the absence of lines in the test areas indicates a negative test result (no antibody).
Kind of like a pregnancy test
In an interview with Ukrinform, an infectious disease doctor, MD, Olga Golubovskaya, said that the rapid methods for diagnosing coronavirus infection have completely different specificity and sensitivity, rather it is screening for self- test. The results of these tests are very dependent on the number of antibodies, therefore, before the 5-7th day of Covid-19 disease, rapid tests are not informative, without “triggering” in its early stages.
On Ukrainian drugstore sites, rapid tests for coronaviruses began to appear in early April. This is mainly the “AT-Coronavirus-test-MBA” test kit from the Ukrainian company “Medbioalliance”, which was put into circulation in Ukraine in mid-March.
According to information on the website Tabletki.ua, which compares the prices of different drugs and medical devices in Ukrainian pharmacies, such a test costs from 350 to 600 UAH. On the manufacturer’s website, its cost is 445 UAH.
ELISA test: there was a virus
ELISA tests are performed on the basis of an enzyme immunoassay. This technique also detects antibodies in the human body. According to experts, the ELISA test is more precise than the express test and gives greater reliability of the result: if the accuracy of the ELISA test is 84%, then the express is around 60%.
ELISA tests are also not intended to diagnose a disease from day one. But an enzyme immunoassay can show if a person has ever had COVID-19, even if it was several months ago.
An immunologist, a Ministry of Health expert, Fedor Lapiy, noted in Radio Liberty’s comment that ELISA tests are for professional use only. In other words, it will not be possible to buy it at the pharmacy, drop a drop of blood and wait for the result. It is intended for professional laboratory use only. The analysis lasts 1.5 to 2 hours.
According to Lapiy, the value of the enzyme-linked immunosorbent assay (ELISA) in its greater precision, a high reliability of the result compared to the rapid test. “The rapid tests and ELISA can detect antibodies, even if the disease was previous, and the doctors missed it. But the reliability of the enzyme immunoassay (ELISA) is of an order of magnitude higher. If you compare that, then, for example, I suspect pneumonia and listen to the patient’s tube, I have it handy – it’s an express test. I want to have a more reliable result, I’m doing an X-ray – it’s an ELISA. If I want to have an even more reliable result, then I use computed tomography – for example, it’s a PCR test, “said Fedor Lapiy.
Ukraine also has its own ELISA tests
“Servants of the People” MP Galina Yanchenko on her Facebook page presented the IFA tests of Ukrainian production of Vitrotest Bioreagent as the first batch of this type in Ukraine. The company’s production capacity is now 200-300 thousand units per month, but volumes can be increased, says Yanchenko.
“Today, the first batch of enzyme-linked immunosorbent (IFA) test systems manufactured in Ukraine for the detection of coronaviruses has been released. We have become the 5th country in the world to do so. IFA tests for coronaviruses are faster and cheaper and can provide mass screening. Such test systems give a result within two hours (PCR – a few days), use Ukrainian-made reagents and will be tens of times cheaper than Chinese and European analogues. The test will be able to detect not only the fact of a coronavirus infection, but also those who are not already the ebolel. This will generate more precise statistics “.
Recently, the Chief Medical Officer of Health of Ukraine, Deputy Minister of Health, Viktor Lyashko, said that mass testing for the presence of antibodies to coronaviruses using ELISA test systems after having verified their effectiveness will begin in the Sumy and Odessa regions.
To date, ELISA tests have been distributed to several state medical institutions for testing. The cost of a study will not exceed 50 hryvnias, promises Vitrotest Bioreagent director Igor Nikolayenko. Although in private laboratories, it can grow in order of magnitude.
Will the effect of mass testing be?
To analyze how much Ukrainians are immune to the virus and what proportion of the population has already been sick, it is not entirely correct to use the term “mass testing,” says Fedor Lapiy. “Because this test is likely to be addressed by those who want to be tested, not by those who need to be tested. Therefore, it will not be the right sample, ”says the virologist. – If we want to obtain objective data, we must then make a representative sample and carry out an ELISA test as a sociological survey. And it will not be “mass tests”, but scientific research “.
If the question is about the need to reduce the risk of contact in certain professional settings, then “mass tests” can be called mandatory tests for representatives of certain professions in which it is important to have immunity.
Warning! There is a suspicion: the test responds to antibodies to different coronaviruses …
Meanwhile, the authoritative German virologist Christian Droosten of the Charite clinic in Berlin draws attention to a drawback of antibody tests. According to him, they often give a false positive result if the patient was sick with a form of the common cold coronavirus other than Sars-CoV-2. Drosten agrees with WHO’s reservations about the potential danger of such a scenario: a person who receives false confirmation of the presence of antibodies can safely neglect the prescriptions and recommendations of doctors and catch COVID- 19. Matthias Ort of the Association of German Laboratory Physicians (BDL) adds that from now on no doctor can guarantee the patient that his body has developed guaranteed immunity against COVID-19. “It is too early to talk about it,” said the specialist.
Oksana Polishchuk, Kiev
According to the materials: ukrinform.ru