You can multiply by 18 to get US units, so 3.4*18= 61.2 in US units. That’s low, but not that bad. That’s about as low as I got after a 4.5 day fast, and I felt perfectly fine, but I always run on the higher blood sugar (morning of 100-110, so 5.6-6.1).
Was listening to a podcast where they were talking about 1 week fasts, and a few of them got into the 30s (1.7 or so). They felt fine.
As already stated, if you have no symptoms (like being shaky, not feeling good, sick, etc.), then it’s probably not an issue.
Also, when I started, I could get into 4 mmol/l ketones after a bit of fasting, and commonly got 3+. Now, I’m shocked when I see >1.0 mmol/l (after 7 more years), but higher ketones aren’t bad.
If you’re concerned about Ketoacidosis, this is high ketones AND high blood sugar. Since you have low blood sugar, you should never be in ketoacidosis.