The new corona virus has only been known for a few weeks. Nevertheless, a team Christian Drosten from the Berlin Charité has already developed a detection method for the new pathogen that is available worldwide.
“We test respiratory secretions, that is, what those affected cough up or a throat swab,” explains Drosten. Doctors must then send this sample to a laboratory that can perform the test. In the beginning it was just the Charité in Berlin, now university hospitals across Germany are able to do this.
How quickly can the sick get a result?
Martin Hoch from the Bavarian State Office for Health and Food Safety put the time in four to five hours. “In the meantime, things are going quickly, since diagnostics are possible here directly,” he said at a press conference after the first case of the new corona virus had become known in Germany.
According to Drosten, the test itself takes about 1.5 hours in the laboratory. The rest of the time is spent on logistics inside and outside the laboratory.
How does the test work?
The process is based on a so-called polymerase chain reaction (PCR). A DNA strand is duplicated in order to be able to detect the genetic makeup of the virus – if it is present. PCR tests are standard procedures in laboratories. They are also used, among other things, to clarify hereditary diseases or to determine paternity.
An advantage of the method is that even the smallest virus quantities lead to a reliable test result. Nevertheless, a negative test result does not completely rule out the possibility of infection, warns the Robert Koch Institute with regard to the new corona virus. For this reason, among other things, not all contact persons from the immediate environment of the infected are currently being tested, said the Bavarian Minister of State for Health, Melanie Huml. Wrong, negative results could be about
due to poor sample quality,
improper transport (the sample should be cooled),
an unfavorable time of sampling or
for other reasons such as a mutation the virus cannot be excluded.
For this reason, the RKI advises that a further examination be ordered in patients with a strong suspicion of the new coronavirus and a first negative test.
How are the samples sent within Germany?
The samples are classified as “biological substance, category B” and must be packed in three layers: first the swab with the smear is placed in a container, such as a tube. This is followed by a second vessel from which no liquids can escape and which is lined with absorbent material. Finally, the third is the outer packaging.
“Shipping should be done via a parcel service and only after consultation with the investigating laboratory”, writes the Robert Koch Institute, On his way through Germany, the parcel must also be provided with the telephone number of a responsible person and the inscriptions “Biological substance, category B” and “UN 3373”. The UN number indicates the risk of contamination of a substance.
The corona virus thus does not fall into the – most strictly regulated – category A. Substances are considered to be substances that “can cause permanent disability or a life-threatening or fatal illness when exposed to otherwise healthy people or animals”. They may only be transported by special companies.