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Why you need to learn your algebra

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#1
hodgsonsurvivor

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I don't know if I'm in the right sub-forum, but I'm glad I'm good at math! In order to figure out how much insulin I need I have to calculate how many units it will take to get me to my goal number plus calculate how much insulin it will take to cover the food I'm about to eat! When my glucose levels are within range, it's easiest...but when they're not...omg...I need pen and paper (and sometimes a calculator) to figure out my dosage! lol Was this method taught to anyone else, or is my doctor somewhere laughing about how silly I am cause I bought it? :)

Here's the formula:

(CGL - TGL/25) + (carbs/10) = n

where
CGL = Current glucose level
TGL = Target glucose level
carbs = # of grams of carbs I'm going to eat (or already ate)
n = # units of Novolog to inject
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#2
Subby

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That looks pretty crazy to me Kristina!! But I am hopeless at maths...

It seems to be tieing the idea of bolusing for you carbs with a correction dose... why not just do them seperately?

It looks like you have an I:C ratio of 1:10 (1 unit:10g carbs)... and an Insulin sensitivity factor of 1:25, were those stated? Assuming that's the case... (sorry if they are not)

Here's an example of an alternative way to do it:

You are 200 and you are about to eat 50g carbs.
You would like to end up at 100 at the end of it all.

First the meal:
50/10 = 5 units to be taken

Then the correction:
100/25 = 4 units to be taken (100 being the difference between current and desired BG)

Total = 9 units

A bit simpler maybe? It also means you can more easily just take for the meal, or just take a correction. Specifically knowing your I:C ratio and ISF means you can adjust up and down if needs be, if you are comfortable doing so (some may feel confident to do so without talking to their doc, otherwise in conjunction with your doc), Good work in working with these calculations, whichever way you use!
20 years T1. NPH and Novorapid.
Some essentials for my blood sugar control: dosing via i:c ratio and cf • basal testing when needed • daily 40 minutes moderate exercise (or close) • carbs somewhere below 120g currently • only eating carbs and carb/fat combos that do not cause a problem spike, with or without insulin.

#3
hodgsonsurvivor

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Lol. Yeah, those ratios are correct! Good job!

Sorry to disappoint you, but your way and my way are the exact same. mine was just written as an algebraic equation. :D

But, it's good to know that it's not just me! lol
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#4
Subby

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Lol. Yeah, those ratios are correct! Good job!

Sorry to disappoint you, but your way and my way are the exact same. mine was just written as an algebraic equation. :D

But, it's good to know that it's not just me! lol


Heh, I'm not surprised... I barely know what algebra is... :) If my doc gave me that I'd be quite confused in trying to use the equation all the time. It makes me wonder if he does it to confuse his patients, but it didn't work in your case! I have known doctors to try and explain things in the least user friendly way possible... to me how information is presented can be as important as the information itself.
20 years T1. NPH and Novorapid.
Some essentials for my blood sugar control: dosing via i:c ratio and cf • basal testing when needed • daily 40 minutes moderate exercise (or close) • carbs somewhere below 120g currently • only eating carbs and carb/fat combos that do not cause a problem spike, with or without insulin.

#5
Scratch

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It's helpful being good at math for a diabetic.

I do all the numbers up in my head. I wish I didn't have to though. It was much more pleasant when the numbers I thought about were baseball statistics.
MDI, Lantus and Novolog
A1c 2/12 -- 5.9%

#6
hodgsonsurvivor

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LOL I usually do to. I only thought of it because my bs was 66 and my target was 100-110 which meant I didn't need to take as much for the meal as I would if my bs was already say 100. I'd just calculate the units for the carbs in that case. lol My brain was a little fuzzy so I worked it out on my calculator (I'm at work!)
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#7
paramountz

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It looks like you have an I:C ratio of 1:10 (1 unit:10g carbs)... and an Insulin sensitivity factor of 1:25, were those stated? Assuming that's the case... (sorry if they are not)


Sorry to thread jack I have never heard of insulin sensitivity factor how do you determine that?

#8
hodgsonsurvivor

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Depending on what type of insulin you're taking, you would see how many points your glucose level goes down after injecting 1 unit of the insulin. You'd want to test before you inject and after the insulin has reached it's peak. I hope I described that right...can anyone second that?
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#9
jenb

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Hi Kristina - yes...I always include a little correction when I calculate my boluses. I target 85 pre-meal, so if I'm under that I reduce the bolus; if over, I augment it. My correction factor is 50 (1 unit of Novolog drops my BG by about 50 points)

I didn't admit to having Math Brain before my diagnosis, but it sure comes in handy now!

Jen

#10
notme

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Oh boy Kristina, If I had to do that kind of math to calculate my insulin.....I might not have survived. I am really hopeless at math.

Maybe that is why my doctor pushed a pump in my direction! :T
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Nancy


“I don't expect everything to be handed to me. Just set it down anywhere.”.




diagnosed type 1 October 1986
currently using Medtronic MiniMed
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#11
paramountz

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Thanks Kristina I have never tried this so do you wait until you are kinda running high then use just 1 unit? I take Lantus and Humalog so i'm guessing the Humalog and testing before and mabey 2 hours after?

#12
hodgsonsurvivor

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Oh boy Kristina, If I had to do that kind of math to calculate my insulin.....I might not have survived. I am really hopeless at math.

Maybe that is why my doctor pushed a pump in my direction! :T


LOL It's funny you say that. But I hear people that say if they had diabetes they wouldn't survive because they hate needles. At some point survival kicks in! lol :)

Thanks Kristina I have never tried this so do you wait until you are kinda running high then use just 1 unit? I take Lantus and Humalog so i'm guessing the Humalog and testing before and mabey 2 hours after?


I'd ask my doctor how to safely find out what your insulin sensitivity is. Are you using correction doses now? My doctor asked me and I guessed when I gave hime my answer, but then I tested my theory and found I was pretty close. My PCP gave me a sliding scale to use and I found that the scale didn't really work for me so I just upped the amount of insulin I took depending on what my glucose reading was. If my blood sugar was 275, I was supposed to take 6 units (2u for every 50 over 150). About 2 hours later, the insulin should be gone or almost gone. Testing again my bloodsugar would be between 110 and 130. If you calculate how far it went down (approx. 150 points) and divide that by how many units I took (6u), you'd say your sensitivity is 25:1. This was a while ago,when I did it, so these example numbers aren't exact. I don't suggest letting your blood sugar get high in order to find out and I also don't suggest only taking 1 unit to find out how far your bloodsugar will fall in order to find out. What I would suggest is tracking it if you can. And this only works, if you aren't adding in other factors like eating or drinking something, stressing your body, being sick, etc. Good luck! :)
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#13
TommyC1

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I wish it was that easy.
I was taught to use a 1 unit of insulin for every 11 grams of carbs (1:11) plus 1 unit of insulin for every 40 mgdl I am above 120 (1:40).
For the easily intimidated g/11 + (mgdl - 120)/40 = u

Unfortunately my blood sugars don't seem to feel limited by the formulas. Or maybe I need to learn to calculate exercise, glycemic index, insulin sensativity and liver function as well.

In any case I generally have to guestimate and correct later.
The calcs are only a place to start.

#14
Subby

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I wish it was that easy.
I was taught to use a 1 unit of insulin for every 11 grams of carbs (1:11) plus 1 unit of insulin for every 40 mgdl I am above 120 (1:40).
For the easily intimidated g/11 + (mgdl - 120)/40 = u

Unfortunately my blood sugars don't seem to feel limited by the formulas. Or maybe I need to learn to calculate exercise, glycemic index, insulin sensativity and liver function as well.

In any case I generally have to guestimate and correct later.
The calcs are only a place to start.


I also find a lot of variability. I wanted to mention the possible importance of good basal coverage in getting results from your I:C ratio. Without my basal right on, the results from my bolus will be some magnitudes more variable.

I'm lucky I went to the pump, because it takes a number of different basal rates through the day to cover my basal sufficiently with neither big highs or crushing lows.
20 years T1. NPH and Novorapid.
Some essentials for my blood sugar control: dosing via i:c ratio and cf • basal testing when needed • daily 40 minutes moderate exercise (or close) • carbs somewhere below 120g currently • only eating carbs and carb/fat combos that do not cause a problem spike, with or without insulin.

#15
paramountz

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Thanks for all the tips I'm happy with my basal just need to work on the correction it's tricky as I race endurance class on mountain bikes so I eat high carb meals to keep the energy up my A1C's are OK at 5.9 and 5.8 the last two I would really like to be at 5.0 once again thank you for the tips they are excellent.

#16
hodgsonsurvivor

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Thanks for all the tips I'm happy with my basal just need to work on the correction it's tricky as I race endurance class on mountain bikes so I eat high carb meals to keep the energy up my A1C's are OK at 5.9 and 5.8 the last two I would really like to be at 5.0 once again thank you for the tips they are excellent.


Hey! Wasn't this my thread? LOL :laugh:
Kristina
A1C 07/08 8.5% :(
A1C 11/08 9.1% :(
A1C 02/09 8.0% :(

#17
paramountz

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I'm sorry please forgive me.




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