Biomedical scientists tasked with analysing coronavirus swab tests have lauded the techniques used in Malta as “very reliable”, confirming these can detect the novel virus “even at earlier infectious stages”.
Times of Malta sought comments from the Malta Association of Biomedical Scientists (MABS) as the number of people testing positive for the virus had started decreasing in recent days. This prompted some to question whether there might suddenly be something wrong with the tests being carried out.
Since registering its first case on March 7, Malta has been at the forefront of testing, carrying out more than 29,000 tests, of which 450 were positive. 286 of these have recovered, while four people have died.
There were no new cases of infection registered on Sunday.
Earlier in April, there had been days when over 1,000 tests were carried out though in recent days the numbers had started to dwindle. The health authorities said this was due to fewer people reporting symptoms as well as some not turning up for appointments.
They have dismissed claims the different types of tests could be resulting in less accurate results.
According to Stephanie Meli, from the MABS, once the tests reach the Molecular Diagnostic Laboratory at Mater Dei Hospital’s pathology department, all swabs are “immediately processed and tested” by trained biomedical scientists.
“The technique used is called rt-PCR (real-time reverse transcriptase Polymerase Chain Reaction) where even small amounts of the virus’ genetic material present in the sample are amplified into larger quantities to be analysed and detected.
“This scientific techniques have a very high average test specificity and sensitivity (over 95 per cent), thus making the results very reliable even at earlier infectious stages where the sample viral load is still relatively low,” Meli noted.
Such a laboratory process takes an average of five hours for each 50-sample batch run. Several runs are carried out during six different times throughout the day – at 6am, 9am, 1pm, 5pm, 9pm and at midnight.
The health authorities have also confirmed that, while still using the same technique to obtain results, various types of swabs were now being used.
On this, Meli said positive cases were detected via all the different kind of swabs used. She also noted that the different swabs did not impact patients’ recovery process in any way.
“The swabs only have different manufacturing brand names. This has absolutely no effect on the sample analysis at the laboratories and thus neither alters the principle of the sample testing nor the accuracy and reliability of the results obtained,” Meli explained.
The only difference between the swabs being used was in the way tests were handled. Each swab had to be transported and stored “as per the manufacturers’ and international health authorities’ recommendations”.
“Some swabs require room temperature conditions while others need cooled temperatures, thus refrigeration is needed during both storage and transportation and until they reach our labs,” Meli said.
From Monday, the health authorities started taking a ‘proactive’ approach to screen for COVID-19, including offering a coronavirus test to anyone who calls the 111 helpline, even if they are not showing any symptoms.