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Hi all, I'm still trying to figure out correction doses of insulin. How do I work out? I'm actually a T1 and basically I've been guessing to some extent but you see I'm pregnant now and I need to control my blood sugar really well. I'm experiencing a few hypos on and off and need to get that under control. So, if I'm not in the appropriate range before I eat, how do I figure out how much extra insulin to add to my predetermined ratio. So far, I've added 1 unit of insulin for each 1 mmol when over 6 (5.9). So for example, if I get a 7 mmol reading I should add 1 unit to the 6 units I calculated for 30 grams. I appreciate any insights and advice. Thanks.



Hi, Looks like you're doing okay so far. I don't know if your diabetes manager told you about the 100 rule and this rule is used to calculate your correction dose of insulin. You have to divide 100 by your total daily dose (TDD). What this gives you is the amount that 1 insulin unit will drop your blood sugar levels by 2 mmol/L. This is one unit of fast acting insulin over a period of 2 to 4 hours. Do keep in mind that this can vary. Some people required 1 insulin unit for every 1 mmol/l increase in blood sugar. While others require 1 insulin unit for every 3 to 5 mmol/L increase in blood sugar. So, let's try a calculation. Suppose say your total daily dose (this includes basal and quick acting) is 80 units of insulin. Then take 100/80 = 1.3 rounded off from 2.5. So 1 insulin unit provides a 1.3 mmol/L drop in blood sugar. Now, this is just a guideline and you will have to play with it a little to get it just right. There are a number of charts online that you can refer to. Just key in the 100 rule for mmol. Some charts will be for mg/dL which is used in the U.S. Some of the charts provide information on meals and snacks throughout the day. I think you'll find this very useful as a backup to your calculations.


Do keep in mind that when you blood sugar levels increase, insulin effectiveness decreases. This will alter the correcting dose and also your basal dose. Individuals often give themselves what they consider a normal dose to correct and find that doesn't work. Then, they end up with hypos.