A new test for the coronavirus is so simple and straightforward, almost anyone could do it: Spit a glob of saliva into a cup, close the lid and hand it over.

While not as fast to process as the speediest swab tests, saliva tests could transform the diagnosis of Covid-19. If manufactured in enough numbers and processed by enough labs across the country, they could alleviate the diagnostic shortages that have hampered containment of the pandemic and offer a less onerous way for companies to see if workers are infected.

The first saliva-based test, already being offered in parts of New Jersey, detects genetic material from the virus, just as the existing tests do, but it avoids a long swab that reaches disturbingly far up a person’s nose. For the saliva-based, health care workers do not need to wear and discard precious gowns and masks. And early evidence suggests it is just as sensitive, if not more so, than the swabs.

Because the saliva test relies on equipment that is widely available, it also offers the hope of a nationwide rollout without encountering the supply problems that have plagued the swabs.