A high-tech laboratory in Abu Dhabi is doubling as a coronavirus test centre for school pupils to help in the UAE's fight against the pandemic.
Biogenix Labs in Masdar City is operated by G42 Healthcare and conducts saliva tests on children aged between four and 12 years old to assist the education sector's efforts to return pupils to classrooms.
The saliva test is less invasive than the PCR nasal swab test and the lab typically delivers results in three hours.
More than 10,000 pupils in Abu Dhabi have already taken the test, either at the lab or at their school since a screening drive started in December.
The alternative to the widely used PCR test is also available to elderly residents.
PCR tests are also carried out on site.
“Saliva tests are safer, non-invasive and more accurate than any test in the market," said Dr Sally Mahmoud, lab director and clinical pathologist with Biogenix Labs.
"The samples can stay overnight on a shelf and can be stored in a fridge for a week.
"The test is not permitted for [most] adults. However, it is shown to be even more accurate than the nasal swab if the 30 to 45 minutes fasting period is adhered to before taking the sample."
Children and elderly residents are asked to not eat or drink for between half an hour to 45 minutes before taking the test, which requires them to simply spit into a cup.
Dr Mahmoud said her team strived for ways to improve the testing process.
“We are continuously looking for new methodologies but it needs to meet our expectations.
"We are very careful with our validation steps and we take our time to evaluate well, we don’t want to use any method that could be misleading,” she said.
The lab has also validated the loop-mediated isothermal amplification test – known as Lamp – which can deliver results in 15 minutes.
It is currently being used for testing international travellers and can be taken four hours before departure.
False positives very unlikely, says lab chief
Dr Mahmoud said when a negative PCR test is recorded soon after a positive one, it is overwhelmingly the case that both results are correct.
In line with health regulations, a positive PCR test must be followed by another test within 48 hours. Many have assumed that this is to confirm the initial result.
However, Dr Mahmoud said that the first result is accurate and there is little room for error unless the sample has been contaminated either at the time of sampling or during sample handling which is “very rare”.
“It is not a false positive, it is a real positive result but with very low viral loads which means the person is at the end of the infection. It is a real detection but could be gone by the next day,” she said.
Another way to follow up with the initial test is to take an antibody or immunoglobulin test.
“That usually confirms the PCR test and usually starts to appear within three to seven days of the infection. It is a requirement with a lot of passengers.
"Some countries insist that both tests are performed and it can be useful for certain cases where a positive result appears and disappears the next day."
