Reliable testing of the Omicron variant

Does my test also detect Omicron?

Every day we receive several inquiries about Omicron and whether this variant can also be reliably detected with the tests sold by Axonlab. The good news right away: Yes, all rapid tests that Axonlab offers are also sensitive to the new Omicron variant and reliably indicate it.

If required we will be happy to send you a confirmation from the manufacturers.

Antigen-test versus PCR-test?

This question is often being disscused and it sometimes even surprises our specialists how many statements are taken as proven knowledge without any questioning. The Axonlab product range includes both antigen and PCR-tests. We therefore have no economic interest in favoring one test or the other.

- A PCR-test is always the better test

- A negative PCR-test guarantees that I am really negative

- Antigen-tests are not as good as PCR-tests

From personal experience I can say that none of the above statements is 100% true. But first thing first.

It is true that a PCR-test is superior to the antigen test in terms of sensitivity due to the methodology. However, this is only true if the quality from the actual testing to measurement is correct. A "sloppily" taken test (e.g. not deep or not long enough) can lead to a false-negative result. Pooling of many samples also leads mathematically to dilution and thus to a deterioration of sensitivity. If, in addition, a patient who is positive despite vaccination and who probably has a low viral load is mixed into a pool with many negative samples, the chance of a false-negative result for this patient increases dramatically.

In the end, the problem is not even the one false-negative patient, but that this patient is now lulled into a false sense of security and becomes a virus spreader.

How good is the PCR-test?

An optimally collected single sample that is PCR-tested for COVID is currently the best method.

However, if PCR-tests are pooled due to increased quantities of tests the quality and herewith the logic of such tests suffer because

1) no timely implementation will be possible any more

2) due to the increased volumes in collecting and in the testing process the routine increases and time pressure becomes even stronger and the test results therefore get less accurate

And what about the antigen-test?

Well, the same conditions in regard to the extraction of the sample also apply to the PCR-test

Carelessly collected samples (unfortunately especially with self-tests) also lead to false-negative results. However, it should be mentioned that the quality of home-self-test are just as good as the antigen tests for professional use. If the result fails, it is because of the incorrect extraction.

When performed correctly, antigen-tests are a very good choice, especially when it comes to mass testing and the question of whether someone is highly infectious.

Which test should be used in which situation ?

Often this is decided by politicians. But let's take a look at an example:

Scenario 1

Monday morning in the classroom, there is a mass gargle testing. Two children are unfortunately positive, which no one knows at this point. Now they don't know this fact all day long, and if things go badly at the mass-PCR-evaluation, they still don't know the next day. The children are together all day and come home in the evening "still healthy".

Then the bad news from the lab. Measured correctly but unfortunately too late. Since it was Omicron, now half of the class is positive. Are you also asking yourself if this makes sense?

Scenario 2

Same Monday morning, this time with antigen-testing. Result after 15 minutes. The two positive children are detected immediately and sent home to quarantine. Of course, a child could be so weakly positive that the antigen-test does not detect it. But such false-negative results also occur with PCR-tests. And how infectious is someone who has already been infected but the antigen-test does not yet respond?

It makes sense to test the highly sensitive areas in hospitals, doctors' offices, and critical infrastructure such as energy suppliers and emergency medical services using highly sensitive PCR-tests. But then please with proper sampling and as a single test or at least in very small pools.

And one more advice for our professional-healthcare-section

If you test a patient positive for Corona with an antigen-test, make sure to send him to the PCR-test for verification. If the PCR-test is negative, then please trust your antigen-test and have the PCR-test repeated. We have more than one example where exactly this happened. Antigen-test positive, PCR-test negative.

We have never encountered a false-positive antigen-test and we have carried out thousands of such tests in our in-house test lab.

Logic tells you that somehow. False-negative results are easy to produce. But False-positive? Something must have gone terribly wrong to make that happen.

Thomas Haller
Member of the Board, Axonlab AG Austria