I can't speak for blood tests, I stopped using a blood test to determine ketosis after a few rounds of buying the strips. They're absurdly expensive, and I find the urine test is good enough for a ballpark idea of whether I'm in ketosis or not, so unfortunately my data may be somewhat suspect.
Nevertheless: today, was in ketosis upon waking according to strips (heavy ketosis). By noon, still in fairly deep ketosis. One hour and three tablespoons of Moi Instant later, I'm only showing trace amounts of ketones according to the strips. That's actually less kava than I was expecting it to take.
Take it for what you will. I'll probably take a 15+ mile ride a bit later, after which I'll test again. I'm sure I'll be back in ketosis as I usually am after decent rides. And then I'll probably kava up again. If past experience is any indication, I would imagine I'll fall back out of it...
Not sure if regular kava use is compatible with a strict keto diet. FWIW, I use keto partially for weight loss, but I also enjoy the positive effects on endurance. There aren't as many peaks and valleys with energy on longer rides/runs, and I never have to bring gels or other snack food along for the ride, just water and a little bit of body fat to consume along the way.
The positive effects on cardiovascular health and the anti-inflammatory properties of the diet are also nice, though my doctor seems to disapprove despite handing her six articles from NIH, JAMA, and other well-regarded and peer-reviewed journals. It's incredible how old health practices die so hard. But, then, she's not a nutritionist, so it's not really her responsibility per se to keep up on the recent literature.
.wimbly