This example above assumes that you have a constant response to insulin throughout the day. In reality, individual insulin sensitivity varies. Someone who is resistant in the morning, but sensitive at mid-day, will need to adjust the insulin-to-carbohydrate ratio at different meal times. In such a case, the background insulin dose would still be approximately 20 units; however, the breakfast insulin-to-carbohydrate ratio might be breakfast 1:8 grams, lunch 1:15 grams and dinner 1:12 grams.

How to work out a correction dose?

Calculating your insulin sensitivity factor

You need to calculate your insulin sensitivity factor to work out your correction doses. To do this you need to know how much insulin you usually take a day.

1. Calculate your average Total Daily Dose (TDD) of insulin over about 4 days
2. Divide 100 by your TDD
3. This is the amount 1 unit of insulin will lower your blood glucose level. This is your insulin sensitivity factor.

You will need to check your insulin sensitivity factor whenever the amount of insulin you take changes, for example

• If your long acting insulin dose changes
• If your insulin to carbohydrate ratio changes

When to give a correction dose:

You can give a correction dose whenever you find a blood glucose level above target before a meal and above 9mmol/L 2hours after a meal.

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