If you are taking rapid-acting insulin (sometimes called meal or bolus insulin, such as Novorapid, Humalog or Apidra), you educator may talk to you about the option of using an insulin to carbohydrate ratio, or ICR for short.
Using an ICR can help you match your insulin dose to the amount of carbohydrate you are eating. This can give you more flexibility in your eating habits, and help you be more accurate with your insulin dosing.
As the name suggests, an ICR is a ratio that tells us how many grams of carbohydrate 1 unit of rapid insulin will cover.
As an example, if your ICR is 1:5, this means that 1 unit of rapid insulin will cover 5 grams of carbohydrate. If your ICR is 1:10, this means that 1 unit of rapid insulin will cover 10 grams of carbohydrate.
If you know what your ICR is, you can use it to calculate your meal time dose of rapid insulin by using the following steps:
- Count how much carbohydrate you are eating in grams.
- Divide the number of grams of carbohydrate by your carbohydrate ratio
- This will tell you how much rapid insulin you should take to cover the food in your meal.
So, let’s use these steps and work through an example:
Let’s say I am planning to eat 45g of carbohydrate at my lunch, and my ICR is 1:15
- I am eating 45g of carbohydrate
- 45g carbohydrate / 15 (ICR) = 3
- I should take 3 units of rapid insulin to cover the carbohydrate in my lunch.
If you are interested in using an ICR, book an appointment with your diabetes educator for help with getting started.
Keep in mind that everyone is different, and will use different ICRs.You may need different ICRs at different times of day or your ICR may change depending on your activity level or if you are sick. Once you are started with an ICR, your educator can help you make adjustments if needed.