The standard RT-PCR (reverse-transcriptase polymerase chain reaction) is and remains the gold standard for the detection of acute coronavirus infection. It is required, for example, to confirm a positive rapid antigen test, people that wish to travel (particularly by air), for clarifying cases with classical symptoms of the common cold symptoms (exclusion diagnostics), or if an individual is a direct contact person of someone who has been tested positive for SARS-CoV-2. RT-PCR is the current most reliable method for the detection or exclusion of a current infection. The detection limit is less than 10 viruses. If the appointment is made during the first half of the day, the result is usually available by the same evening. The result is available within 24 hours after sample collection.
The express RT-PCR is the same method as the standard RT-PCR, with the exception that the result is available after 3-6 hours. Only certain online appointments are available for the express PCR service, as the logistical effort is significantly higher. The express PCR test is required, for example, in cases of spontaneous travel or for other reasons where a quick clarification is required.
We are the FIRST test centre in Berlin to offer a real-time PCR to test for SARS-CoV-2 variants. With this service, two different PCRs are performed. First, the standard PCR is carried out, where a positive result is confirmed. Second, an additional PCR is conducted, to test for the different variants.
As described in various media sources, there are several variants of concern. The UK variant is somewhat more contagious and associated with more severe symptoms than the Wuhan variant (wild-type). However, currently available vaccines are effective against these variants. In contrast, the South African variant has mutations that make vaccination against this variant less effective. For individuals that highly suspect that they may be positive, this particular test may be of greater interest.
The result is available within 48 hours after sample collection. after sample collection.
Limitation: The variant PCR only works with a clear viral load (i.e., a CT value fewer than 33 cycles). If individuals have selected this option but, for example, a suspected infection is not confirmed (i.e., negative PCR result), an additional PCR for variant analysis will not be performed.
The rapid antigen test is an ideal option for quickly identifying highly virulent individuals. Viral proteins Here, only viral proteins are detected. The PCR requires less than 10 viruses for a positive result, as the viral RNA is transformed into DNA and amplified during the PCR reaction. In contrast, the rapid antigen test requires more than 200-300 viruses to obtain a weak to strong positive signal. However, it remains an important tool to control the spread of the virus, especially during the current pandemic, and for monitoring the incidence of infection. Unfortunately, rapid antigen tests can be positive in rare cases, even though the test individual is not infected. Therefore, a PCR is required for every positive rapid antigen test. Also, a negative rapid antigen test does not definitively confirm that the test person is negative. Therefore, PCR is and remains the gold standard for the reliable detection or exclusion of current infection with SARS-CoV-2.
The test centre at Leopoldplatz belongs to DHS - Diagnostic HealthCare Solutions GmbH, a spin-off of the Berlin Charité. We develop our own solutions to improve diagnostics and are currently planning to offer you further laboratory services in the near future.