Understanding Ratios

[Funnygrl]

Right now I am using a 1:20 ratio for carbs, and correcting 1 unit to lower me 50mg/dL.

If I am eating and want my bs to go up 50 md/dL, is it okay to just leave out 1 unit from the meal bolus? Or a half unit if I want to go up 25md/dL?

And does all this mean that without a bolus, 20 grams of carb would raise me 50mg/dL?

Basically what I am asking I guess is if 1 unit lowers me 50mg/dL, will leaving out 1 unit raise me 50mg/dL? Can you work the algebra like that?

[Cyborg]

I think you are confusing 2 different ratios. You may be confusing the insulin to carb ratio with the insulin to bg ratio. They are ralated through a formula:

http://www.insulin-pumpers.org/howto/HOWTO-calculate-CBS-1.shtml

[Funnygrl]

No, I am not confusing them. I am wondering if I can use them both to figure out how many carbs I need to eat to raise my bs 50mg/dL.

[Funnygrl]

Ok, that calculator told me what I wanted to know. 1 gram of carb will raise my bs 2.5 mg/dL. Based on the calculator they are related how I suspected they were, since I was asking if leaving out one unit or eating 20 grams of carb will both raise me 50 points, and they will if this calculator tells me 1 gram will raise me 2.5 points, since 20+2.5=50.

[Erin]

A word of caution tho: I asked my Doc the same question when I was first put on these new fangled ratio thingies (well they were new fangled at the time anyway) and she said, yes, i theory it would work the way you describe, but she cautioned not to do that if your Bg was low, or close to being low... That you should treat the low with juice or glucose tabs, and then bolus for the meal as usual. She said while the algebra works, the timing often doesn't, and you could end up going lower before going higher.

[seacomp]

She said while the algebra works
Well, the algebra works when you are at or near the normal range. If you are way off, either high or low, the simple relationship does work. :evil:
If you are very high, you need more insulin than the ratio suggests to lower it to goal; likewise if you are very low you need more carbs to raise it back.
This is why you correct; retest; correct again, in such situations.
For the example given - raising BG by 50 points, it makes a difference if you're at 50 wanting to be at 100, or if you're at 100 wanting to be at 150 (so you can exercise, for example). For the second case, an adjustment in the bolus should work just fine, for the first, you'd want to correct first.

[am1977]

This may be a repeat of what you already know, but this is what I've been told.

If you are low, it's at meal time, and you dont' want to eat extra food to treat the low...you could try this simple equation:

current bs - 100 (target bs)/ 50 (correction factor)= how many units to leave off.

Example if I was low: 50-100= -50/50= -1 unit taken off your bolus.

Hope this helps ;)

[JediSkipdogg]

And just so you know that is the formula that the Animas 1200 and above pumps use if you use the carbsmart + ezBG feature. It adds up the amount of insulin you should take for the carbs you are eating and then it subracts out the amount of insulin you should NOT take for running low and tells you what to give.

[Tokyo Cate]

I asked my Doc the same question when I was first put on these new fangled ratio thingies (well they were new fangled at the time anyway) and she said, yes, i theory it would work the way you describe, but she cautioned not to do that if your Bg was low, or close to being low... That you should treat the low with juice or glucose tabs, and then bolus for the meal as usual.

I am with you, again, Erin. These new fangled things can be tough to get your head around. Good thing I have the Forums land to come to!

[vrocco1]

Is your correction based on experimentation, or just a guess by the Doc? Usually, corrections are on the cautious side, that's why it pays not to mess with it when you are on the edge of being hypo..

[Funnygrl]

And just so you know that is the formula that the Animas 1200 and above pumps use if you use the carbsmart + ezBG feature. It adds up the amount of insulin you should take for the carbs you are eating and then it subracts out the amount of insulin you should NOT take for running low and tells you what to give.
Ok, brought back this thread cause I was thinking about this again tonight. Cozmo does the same thing.

My doctor wants me to try and test my ISF more, but I don't go high very often, and I don't want to try and go high to test it, so I was wondering if it was possible to test it just by seeing how high I go by lowering a meal bolus by one unit?