New way of measuring blood volume


Active Member
There is a relatively new method of measuring blood volume – carbon monoxide rebreathing. It is much cheaper and easier than the old way (nuclear isotopes).

It is being used at NASA to study hypovolemia in astronauts, as well as in sports science and altitude studies.

This machine is undergoing approval for medical use this year. It is made in Denmark. The company has a scheme to lend out a machine for two months free of charge to scientists who will put it to good use.

I think this will allow scientists to finally do some good research on low blood volume in ME/CFS and orthostatic intolerance because it will be much more affordable.
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Active Member
Here is a video of the test. Note: shows blood being taken.

Anyone who is qualified to take blood can easily be trained to run the test. No nuclear medicine qualifications required!


Active Member
The medical version has now been certified for use in Europe. We should see it showing up here and there very soon!

The company has a free loan program, allowing any interested scientists or doctors to apply to borrow a unit:


Active Member
Where did you find out about this loan program?
It’s on the company’s website at the link I posted above (looks like a blue square rather than a URL). It’s for interested doctors or scientists who can install the device temporarily in a suitable lab or clinic.


Active Member
Some research on blood volume, done with the older isotope method:

Blood Volume Status in ME/CFS Correlates With the Presence or Absence of Orthostatic Symptoms: Preliminary Results

In the next few years, we will see CO rebreathing blood volume testing available in hospitals and autonomic labs.

Low blood volume can be addressed with volume expansion (e.g. increased salt and fluid intake, fludrocortisone) and volume redistribution (e.g. compression leggings).

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