During nutritional ketosis, it is normal to have blood ketone levels of 0.5–3.0 millimoles per litre (mmol/L). Below that you're burning carbohydrates, and not (much) stored fat.
We all produce small amounts of ketones, especially during the night. It is normal. No need for concern if they are below 3. Ketones become dangerous when the go over 10. DKA symptoms are also very clear - shortness of breath, heart palpitations, no energy.
