Washington, United States | AFP

US President Donald Trump on Monday announced the distribution of 150 million rapid coronavirus tests ordered from Abbott Laboratories that are able to deliver a result in 15 minutes and display it in a similar format to a home pregnancy kit. 

"Here's our plan: 50 million tests will go to protect the most vulnerable communities," such as nursing homes and assisted living facilities, said Trump.

He added that the other 100 million tests would go to states and territories to assist them in opening their economies and schools.

Each of the kits cost the federal government $5, and the health department said in a statement that Abbott plans to make 48 million kits available monthly in the coming weeks.

Experts have for months been calling for widespread adoption of this low-cost technology, called antigen tests, so that people can test themselves several times a week -- though the current approval is only for the test to be performed by a health care professional.

The turnaround time offers obvious advantages for stemming the spread of the virus.

But it comes with a trade-off -- they are less sensitive than the standard polymerase chain reaction (PCR) tests and therefore more likely to return false negatives.

This is because the PCR tests use sophisticated lab equipment capable of detecting trace amounts of the virus' genetic material. 

But if it takes a week or so to return a result, a PCR test isn't clinically meaningful as the patients have either already recovered or become more obviously sick.

On the other hand, antigen tests work best when a person has a lot of virus in their nose, which is probably also the point at which they are most contagious.

The tests use a paper strip containing coronavirus antibodies that react when they touch the virus's spike protein, similar to how a home pregnancy test reacts to hormones.

However, the antigen tests may require further confirmation by a PCR test, particularly if a person tests negative but appears to have symptoms, since this could mean the bulk of the virus has migrated from the upper to the lower respiratory system.

Reacting to the news, Harvard epidemiologist Michael Mina said the Abbott test order "is terrific and is a great start."

But, he added, the amount being distributed by the government was "simply not sufficient" and production should be multiplied ten or twentyfold.