On the other hand, if you are loosing weight, you are not having 'hangry' sugar drop episodes and you know you are keeping your net/total carbs low you will be running on burning fat rather than sugar for a fuel. So it doesn't matter if you are showing excess ketones in your blood or in your pee or not.
While being in Ketosis is a monitor of this it's really the switch your body does to being 'fat adapted' that counts and actually while it's easy to drop out of ketosis after a higher carb day (or meal in my case!) it's not as easy to stop your body being fat adapted. Once you are 'fat adapted' then that's it's preferred fuel basis and it doesn't change that after a meal or even a day or two even if a ketone measure doesn't show anything.
However if it interests you then go ahead!