https://www.ncbi.nlm.nih.gov/pmc/ar...21242-fig-0002/

Perspective... breath acetone has a fair correlation to blood ketones.

But here's a graph showing that correlation. in individual data points--an example, at around .25 mM blood hydroxybutyrate--not very ketotic-- points span from what looks like around 10 nM to 140 nM. There are data points at 2.5 mM blood ketones with breath ketones no higher than that 140 nM. A correlation is not the same as the ability to predict actual blood ketones from breath ketones.

Blowing acetone just after working out gives you a data point. Try doing it nowhere near your workout on the day after pizza.