Watching Chris' video here, "US Doctor, How can you make a vaccine for something never proven to exist?", I hear that the Coronoavirus test involves testing for "exosomes". For the lay person to understand, it may help to know what that means.

For every time I've heard the term "exosome" used, I've heard the previous term, "vesicle", used a hundred times. They are the same thing. Imagine a microscopic gel cap, like a vitamin E supplement, but containing various biochemicals (lipids or fats, RNA, DNA, neurotransmitter chemicals like dopamine, etc). Like those vitamin pills, vesicles are "membrane bound" (surrounded by a flexible wall). The are produced inside the cell and expelled.

They were until recently thought to be simply cellular waste. Except for the ones that contain neurotransmitters. Some probably are waste. However, newer research ascribes various possible functions to them. I'm going to have to read the papers the Doctor mentions, but it sounds like they are testing for vesicles that are produced as part of an inflammatory response to the virus. However, apparently these same ones can be produced as a response to a variety of factors, including the flu and lung cancer.

This detracts severely from the credibility of the test, of course. It's too non-specific, and some of the other factors (flu) are too common to, say, use as the basis to shut down your national economy. Very much so.

In addition, "The investigation into the formation and role of exosomes in viral infections is still being elucidated." Sep 28, 2018 - The Open Virology Journal Article abstract here

So it can't really be called a well-characterized connection yet.

Wiki page for Exosomes