Can someone help me determine correction factor?

When I was “trained” on the Dexcom G6, the CDE told me to use 1 u for 35 mg/dL correction, and to use 130 mg/dL as my correction target. (I use MDI with Humalog and 1 nighttime bolus of Lantus.) I think my Lantus dose is pretty good (14 u) as I tend to trend gradually, very slowly, down most of the time. (During the day and night.) I do pretty well, stay pretty steady, as long as I don’t get a high. My highs most always come from rebound over-correction of a low. I’ve included some graphs to illustrate what my normal days look like. (And I do get peaks from meals, but usually nothing that goes out of bounds.) (Sorry the graphs are out of order, but you know how Dexcom does this.)

But, it’s pretty obvious to me that the 1:35 correction factor is wrong, and can’t I use a lower target to correct to? If I’m trying to maintain something between 90-100 mg/dL, then why would I correct to 130?
So here’s yesterday (low down to 51, over-corrected) and last night (200s all night).

I need a better plan of what to do to bring down the 200 high. I did take 1/2 u Humalog before bedtime (the 1/2 u for no reason other than I don’t know the “correct” correction factor, and I’m new to corrections and hesitant to take too much). Obviously it didn’t do anything.
So this morning I was 180 mg/dL, and I used 90 as my target and tried 1:30 as the correction factor. I had 24 g carbs (which I normally take 5 u, my morning I:C is 1:5), so I took 5 carbs + 3 correction when I ate at 9 am. (also prebolused about 1/2 hour) Is this what I should expect as a “correct” correction? I’m sitting here now at almost 1pm and I’m 78 (no lunch yet).
I hope this isn’t too personal, but the CDE and PA just look at my graphs and say “Yup, looks good.” I don’t get any feedback or suggested tweeks, etc.
Any suggestions welcome.


@Jan Looking at your graphs I’m hardly one to give advice. But if you want a correction to about 15% lower than the CDE gave you, just adjust your correction dose calculation by about 15%. ie instead of 1u to 35 mg/dl use 1u to 30 mg/dl. See how that works and make small adjustments from there.

PS: I don’t mind over correcting a little bit because it’s so tasty to eat out of a low :yum:.


Yes, you can correct to anything you want. I think correcting to 90-100 is better.

A lot of times the advice you get is overly cautious. It’s a frustrating reality, but the higher BG causes you long-term damage. A very severe low - like one you do not recover from or one that causes a car crash or a low where you spend hours below 40 - those severe lows can cause damage immediately.

So in the CDE’s mind, they want to avoid a severe low, but it comes at the cost of more long-term and slower damage.

That is where we want to balance an aggressive high correction, and the acknowledgement that you need to be careful with it and not allow it to cause you an extreme low that you cannot respond to.

It is not linear. What I mean is that whatever correction factor that may work for you at 150, may not be sufficient at 200 or 250. The higher you go, generally you will need even more of a correction factor.

Do you feel lows? Are you comfortable being more aggressive with your high BG corrections and being able to treat a low if you need to?

My general belief on it, in simplest terms is this:

  • Be aggressive treating highs, be conservative treating lows.

I think that fits in with this :arrow_down: comment.

I think this is much better. Keep in mind, the higher you are, the more aggressive you may need to be. Like in this example, a correction of 1:30 worked okay. But if you were 250, you might need 1:25 or something like that.


What about timing of corrections? Currently I only correct with a meal bolus. What are the guidelines for correcting at other times? Do I need to wait a certain amount of time after a meal bolus? I’m just now getting comfortable being low at a meal and still bolusing the appropriate amount and waiting to eat (pre-bolusing).


I do it whenever it is necessary.

It takes time to get comfortable with it. Like to know how much your insulin will come in later.

If you look at insulin’s activity (just an example picture here for Humalog, your results may be different), look at how much more you get in the first hour than in the next few hours.


It takes time to get this sort of stuff figured out.

Like if you have just taken an injection, you will have a lot of insulin coming in. But if it has been a few hours, most of your insulin has already come in, but you have a little bit left that will come in still.

So your corrections should be based on all kinds of things:

  • how recently you took your insulin
  • how recently you ate
  • how soon you will be eating again
  • if you are going to be awake and can tread a low BG
  • if you are going to be asleep and can NOT treat a low BG

So, I think you can correct anytime, but you have to start analyzing how much you need to correct and how much insulin will be coming in and how much food will still be coming in, and how high your BG is and how fast it is going up…

There are a lot of considerations.

It might help to walk through some general examples of situations.


I ended up with a completely different approach to the one recommended to you. This approach was not recommended to me; as @Eric implies the medical profession is really scared of low blood sugar because it can result in lawsuits, whereas consistent high blood sugar over our lifetime won’t.


My target BG is 80mg/dl and my Omnipod is currently set to do corrections regardless of my blood glucose, but that doesn’t mean I allow it to; I only enter the BG when I want a correction :wink:

My correction factor is 50mg/dl/IU; so that is actually much less aggressive than your 35mg/dl. It’s an undercorrection, but I regularly stack corrections and for high blood sugars I use my intuition and enter a number of units.

My basal is actually 12IU/day, so lower than yours and if I don’t eat I will end up flatlining, but that means my bolus has to cover protein and fat as well as the carbs. I regularly do temp basals at quite a high level to handle that, but temp basals aren’t possible on MDI.

This doesn’t necessarily work any better than what you have, indeed my last few days graphs are no where near as good as yours.

The real difference here is that I handle the risk of lows by undercorrecting, whereas your recommendation was apparently to use something close to the correct correction factor but target a much higher BG. Thinking about it that might be a better approach because my ad hoc target range is actually 100-150; I get careful below 100 and start preparing to correct for a low and in practice I only do a correction bolus above 150.


Would the following be correct:
In order to determine the correction factor for BG near 150, my BG would need to be 150, and have zero IOB.

In an ideal situation, let’s say if my BG= 150, it’s pretty flat, zero IOB, I take 1 unit and my BG drops 25 points in the first 30 minutes. what is the correction factor? Or do I have to wait 1.5 hour to measure the bg?

When folks say, for example, that you know your correction factor is, for example, 1 unit of insulin for 35, when do you measure the lowered BG? @ 30 minutes, 1 hr, 1.5 he, 2 hr, or 3.5 to 4 hours after the correction injection?

I can see that this test result is more easily visible if BG=300 than say BG=150. The BG decrease would be greater. However, the correction factor would be different at 300 than 150.

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When you look at typical action curve durations, I personally would define the correction factor at 3 hours. i.e. how many carbs did it cover in 3/4 of it’s action. Others might use a longer duration, but I don’t think anyone would use 1 or 1.5 hours.


In the experiment you defined, I would see how much lower you were at 3 and 4 hours and determine your correction factor based on that info.


I agree with this as starting point of calculation, but then adjust for different factors such as exercise (planned or “on board”), and other things like stress, illness, etc that are causing insulin resistance. With experience, this calculation happens without much effort.
And then there are times I over-correct in anticipation of a snack later if needed.


3-4 hours make sense.

For me, most of the time, 2 hours after bolus, there is very little change in BG. Could this be caused by the use of the 8 mm pen needles? For a regular meal, I inject in my abdomen or the fattier part of my thighs. If I’m trying to correct, I inject in my calf, or deltoid.

I don’t think your 8 mm needles would slow thing down, in fact I would guess they are speeding things up. So the little change in BG would be better explained by other factors in my opinion.

I agree with you that 8mm needles should make insulin work faster than 4mm needles. I’m fat in my abdomen and thighs - If the 8mm cause the insulin to go into partly IM and partly subq would it start to work early and finish early too?

If standard subq starts working in 30 minutes and peaks at 1.5 hour and stays in the system until 4 hours,

Would IM (or partly IM and partly subq) start maybe 15 minutes and stay in the system for less than 4 hours? Everyone is different so the numbers may vary. I’m trying to get a sense.

Everyone who uses IM has said that the insulin begins working faster. Is the duration of insulin activity less for IM than subq?

Specifically, for corrections, I’ve noticed that my BG’s don’t seem to change at the 2 hours after correction bolus.

I think you are correct in your thinking. IM probably moves everything about 15-20 minutes faster for us, including clearing out of the system.