Saliva Tests  

#GS3 #Science #COVID19 

Recently, the US Food and Drug Administration (FDA) approved a new method of testing for Covid-19 — processing saliva samples — and termed it “ground-breaking”. 

  • Like RT-PCR, a saliva test too detects the virus. It converts the virus RNA into DNA, then amplifies the DNA to detect presence of the virus. What makes the SalivaDirect kit unique is that the Yale researchers have done away with a separate step or specialised equipment to extract the virus RNA. 
  • Difference between RT-PCR test and SalivaDirect test? 
  • RT-PCR test is a traditional molecular test which is invasive and can have false negatives since it triggers irritation. It relies heavily on PPE gear to keep away droplets from infecting healthcare worker. 
  • However, the latest SalivaDirect Test is less invasive and it is much safer for healthcare workers collecting sample therefore PPE kit usage is reduced by nearly 90 percent. 
  • Unlike the traditional RT-PCR method, the SalivaDirect test does not require saliva collection tubes to have preservatives nor does it require specialised reagents or equipment for nucleic acid extraction. 
  • However, there is a concern with SalivaDirect Test. The negative result do not preclude SARS-CoV-2 infection. It will have to be complemented by other clinical observations. Saliva from patients can contain blood or mucus that can make it difficult to pipet (pour). 
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