Saliva Direct

Subject: Science and tech

Context :

A new, rapid diagnostic test for the novel coronavirus that uses saliva samples was granted an emergency use authorisation by the U.S. Food and Drug Administration (FDA).

Concept :

• The inexpensive test called SalivaDirecthas high sensitivity and can detect the virus even when the number of virus copies in the saliva sample is as low as 6-12 copies per microlitre.
• Collecting and testing saliva samples involves three steps — collecting saliva without preservative buffers, proteinase K treatment and heat inactivation, and dualplex RT-qPCR virus detection.

Significance:

• The new saliva test would increase efficiency and avoid shortage of crucial test components such as reagents.
• The new test makes sample collection non-invasive and reduces the need for trained healthcare workers to collect the samples, reducing the risk of infection during collection.
• In contrast, tests using nasopharyngeal swabs lead to false negative results due to errors at the time of sample collection.