The Collinson, Swissport and Heathrow Airport consortium have issued a statement explaining the background to Covid-19 testing. 

PCR (polymerase chain reaction) is the most sensitive test that is currently available, able to detect active infection some days before the patient is infectious or symptomatic. It is the gold standard test; used in the NHS daily. PCR testing takes around 5hr to be performed, but as assays sometimes have to be repeated, a turnaround time of 24hr is often given.

PCR testing is performed in machines than cycle through different temperatures. As the process of changing temperature takes some time, the process is longer than other processes such as LAMP.

LAMP (Linux, Apache, MySQL, PHP/Python/Perl) is another form of genetic test, able to detect the RNA (ribonucleic acid) of the virus. It is a more recent development than PCR and is performed all at one temperature. It is generally faster and cheaper than PCR but is not considered to be as sensitive – but is still more sensitive than antigen testing. LAMP tests might be able to detect patients immediately before symptoms are displayed but this is unsure at present.

Rapid LAMP testing can add a significant degree of confidence if performed before flying, for example, when all aboard have had a LAMP test prior to departure.

Antigen Testing is the fastest and cheapest of all lab tests for Covid-19. Unlike PCR and LAMP, the genetic material of the virus is not searched for, but rather the protein structures on a virally infected cell produced by Covid-19; usually the so-called ‘spike’ protein. Antigen tests often become positive after having had symptoms for a couple of days.

Their use is particularly powerful when patients are attending communal events and a quick check needs to be performed to see if attendees are infectious with Covid-19. Also during winter months, when people often have symptoms of the common cold or flu, performing an antigen test will ascertain whether the condition is the coronavirus or not.

See Testing at Heathrow in this week's BTN.