Analysis of the types of samples that could be handled by RT-qPCR COVID-19 test in Singapore

One of the major hindrances towards getting more people to come forward for voluntary testing is the perceived unpleasant nature of nasal swab. Thus, there is an ongoing effort in clinical diagnostics for SARS-CoV-2 to expand the types of samples that could be used for accurate, fast, and easy detection of the virus. But, different types of samples such as those from the throat or saliva carries different fluid elements or enzymes and inhibitors to PCR. Hence, developing a PCR master mix cocktail that could handle or at least ameliorate the potential inhibitors in different sample types demands additional chelators or other components that would inevitably add to the cost. In addition, some of the additives that could chelate PCR inhibitors are proprietary or protected by patents, and would thus not be available to biotech start-ups interested to expand the types of samples that could be handled by their diagnostic kits. A meta-analysis of the documentation supplied by companies developing SARS-CoV-2 RT-qPCR test kits in Singapore under the provisional authorisation regiment reveals a preponderance of tests capable of handling nasopharyngeal sample. As can be discerned from the data, no tests developed in Singapore could be applied to nasal aspirates, nasopharyngeal wash/aspirates, bronchoalveolar lavage fluid or sputum sample. In addition, most of the tests could only handle one or two types of samples with nasopharyngeal and oropharyngeal being the most common.