Corona test streets may soon receive a “fast lane”, for people who receive priority because they, for example, teach or work in healthcare. This is what researchers expect from TNO, who, together with the GGD Amsterdam and RIVM, have developed a test that gives results within an hour.
During the testing itself, one will not notice much of it: a cotton swab sample is still required for the test, with tissue from the throat or nasal cavity. Only the analysis that follows is a lot faster. That makes the test also useful for applications at airports, TNO thinks: ready while you check in or out.
The rapid test is a so-called “LAMP” test, a technique for analyzing genetic material that was invented 20 years ago in Japan. But now scientists led by TNO researcher Bart Keijser have made the test suitable for the corona test street: with as little material as possible, and supplies that are not already needed for the increasingly scarce ‘normal’ corona tests. For example, the LAMP test uses enzymes that can be manufactured at DSM.
“It all looks very favorable,” says Keijser, who recently tested the technique in a lab on a number of previously collected samples from real corona patients. “The technique is so far as sensitive as the current PCR test, and is unresponsive to the presence of other cold and coronaviruses.”
Whether this will also remain the case with larger numbers, the next round of research will reveal. In a week’s time, the team wants to have the test run in the background at the test street in the RAI Amsterdam with the regular cotton swab test, to check whether it gives the same results. And to gain experience with all kinds of practical matters, says Keijser.
Magnetic beads
LAMP stands for the chemist’s mouthful of “loop-mediated isothermal amplification”. After taking the throat sample, the virus is broken open, the genetic material fished out with microscopic magnetic beads, and propagated by using self-starting DNA fragments. This makes the technique much faster than the old, “PCR” (polymerase chain reaction) method, in which the reaction has to be pushed up each time by raising and lowering the temperature.
The LAMP test is not the only rapid test under investigation. For example, various “pregnancy tests” are on the way, tests that check within fifteen minutes whether there are virus proteins in a throat sample and show this with a dash. Also on the way: a breathalyzer test, which uses certain molecules in the breath to read whether there is a virus infection in the throat. The tests will be tested for reliability in practice in the coming weeks, says RIVM virologist Chantal Reusken, who coordinates the control studies.
Pre-selection
The rapid tests are primarily intended to relieve the current, overloaded test lines. For example, a rapid test could make a pre-selection of people who certainly do not have the virus, after which the remaining ones would be thoroughly tested again with the more precise PCR test, which is actually intended for hospital patients.
The LAMP test can run on existing equipment as well as on simpler, other analysis machines, says Keijser. In addition, the test is about half as cheap as the PCR test, which costs around 65 euros. “And I think it can be reduced even further,” says Keijser.
