If you do a low carb diet, your blood glucose should come down and spike less. In that case, you should not need to check for ketones. They don't start forming until your blood sugar is high (around 12 or above, as far as I recall).
Ketoacidosis is more common in type 1 diabetics who have no insulin of their own and cannot do sugar-metabolism without help from injected insulin.
If you do get very high blood sugar readings for any reason, do check, of course. However, a low carb diet should make it less likely to happen at all.
So, if you have high blood sugar, test. If you low carb, you should NOT have high blood sugar (as much). Bottomline - I would not be worried, on the contrary.