My five-year-old son has had type 1 for over three years. He’s on a pump and uses NovoRapid. We’re checking his sugar level around six or seven times a day. Of course, if he has lows or highs, we check more often.

My question is: is it necessary to check ketones? We know that high ketones can lead to DKA, but we know we have to try to bring it down to a normal level. So, it’s obvious that if level is high, ketones will appear sooner or later. To be honest, we have not checked for ketones for a year and a half. Usually, if he goes low then he eats something and then goes high, we give him extra insulin. If the high was high (above 300 mg/dl [16.7 mmol/L]) or really high (above 400 mg/dl [22.2 mmol/L]) we’re testing his blood sugar once again after 90 minutes or two hours and if his blood sugar is still high, we check if everything is fine with his infusion set/pump. Then, we re-check the blood sugar again and if remains high, we change the infusion set and site. This practice gave the result of an HbA1c in the range of 6.2 to 6.7. The highest that we had was 7.4, but it was at the beginning of our journey with diabetes.

As you know, insulin pumping provides a continuous infusion of a rapid-acting insulin. But, one of the potential disadvantages and drawbacks about insulin pumping is that, if there were an interruption in the flow of insulin (e.g., pump failure, site insertion problems, tube kinking, etc.) then there would be NO insulin available. At least with insulin injections, there is the combination of some rapid acting insulin (the boluses with meals) but also injections of longer lasting insulins that functions between meals.

Ketones can typically begin to be produced when the serum glucose gets to 240 mg/dl [13.3 mmol/L]. I advise my patients to start checking for urine ketones (or blood ketones if they have a special meter with its special strips) when the blood glucose is more than 240 mg/dl [13.3 mmol/L]. Many colleagues will say to start checking for ketones when the glucose is more than 300 mg/dl [16.7 mmol/L].

I strongly advise that you check for ketones when your child’s glucoses are in the elevated range. Furthermore, as you alluded to, the presence of ketones also inhibits some of the actions of insulin so, if you know that ketones are present, then you can adjust any corrections accordingly.

Certainly, you should get the input from your child’s own diabetes healthcare providers but I say don’t start looking for ketones by the time the child feels ill. Check early!

DS