Need help with my I:C and ISF

I feel I should know how to answer this, but I don’t…

Current Basal 1.8u/hr all day except 2.0u/hr from 2am-8:30am.

Woke up today and decide to test things out. At 7:30 am I was 173. I had some coffee with Splenda and by noon I was 195. I knew I was running on the higher side, but wanted to watch my BG trends on my Dexcom sensor through lunch. At lunch I consumed a measured 52g of carbs, for which I took 3.45u (1u/15g). Nearly 3 hours later, my BG is 236. How much should I adjust my I:C ratio by? For a correction to the 236, my Ping calculated that I needed 4.53u (1u/30mg/dL) minus the .43u of active insulin, giving me a total of 4.1u for a correction. If all goes well, in an hour and a half I should be down to my target of 90-110mg/dL.

Any suggestions? I’ll post in a few hours to see where my BG lands.



Before you try to test your I"C ratio, you should do some basal testing - if your basals are not right, you can test your carb ratios all you want & they won’t come out right. To do basal testing, you don’t want to eat or drink stuff like coffee. Once you know your basals are right, then I would do a simple carb test - eat something small like 15 grams of carbs (or less) so you only use 1 unit of insulin.

I agree with Kelly about the basal testing, Mike. If you are frequently waking up at 173 you might want to up that early morning dose to see if you can wake up lower. For me I found my basals were more variable than that, and I have 6 separate “time zones” that I determined by time periods where I was too high or too low.

A couple other observations: If I wake up high, I will usually do a correction right away so by the time I’m ready to eat I’m starting out in a better place. I find that if I’m high before meals it’s hard to break the trend of going up further such as what you describe.

Second, at lunch you were 192 and you bolused just for the carbs you were eating, so even though you rose a reasonable 40 points it put you to 236. That’s what I mean about the trend of going up and up. I would have tried to break that trend in one of two ways. You could correct and wait to eat till you are more in range, or, since that isn’t always practical, you should have added a correction amount into your bolus. You needed both a bg and a carb bolus to account for your high blood sugar and what you were about to eat. Also, if I were that high before eating I probably wouldn’t eat that many carbs. I know we are all different in how many carbs we eat, but you might plan some meals you can have when your blood sugar is already high that are a bit less carb laden. I hope the correction for the 236 works well, but my suggestion would have been to nip it in the bud much earlier.

I don’t think you can decide on a change to your I:C based on this experience, because you were already high. What I suggest is to keep records for awhile when you are in range before your meal, and see how often your I:C is successful in keeping you in target 2 hours later. If you frequently end up too high than try reducing that ratio from 1:15 to 1:13 and see how that works for a few days.

But yeah, I agree, that you should get your basals set right first before you work on the I:C’s.

The Animas documentation tells how to do basal testing. Do the basal testing Kelly suggests with one change. Since you have a Dexcom, keep it tight to your real BGs by doing a BG every 2-3 hours and entering it into the Dexcom. Contrary to some posts on this and other D sites, too much data will not trash the calculations of the Dexcom unit.

Second, what was your I:C ratio before pumping. I:C should not change drastically.

Third, did you have a correction (ISF) when you were doing injections? For example, if BG >250, give 5 units regular and recheck BG in 2 hours, etc.

Hope this helps. Kelly and Zoe are very wise.

I agree that you should basal test first. Much of your highs could be caused by a need for more basal, not a need for a higher I:C and ISF. If you can get a relatively flat-line when fasting and adjusting your basal, you’ll know it was basal that needed adjusting. If you get that nice flat-line while fasting/adjusting basal BUT you continue to have highs after eating…then you can start to look at I:C ratios.

I make adjustments all the time to my ratios…but my basal is always the first one I look at, and it gets adjusted far more often than I:C or ISF.

Well can’t tell you how to set your ratio and isf it has to be your doctor. Have you discussed this with you health provider?
I would contact your doctor. Good luck

Many of us set and tweak our own numbers, Darlene. I would go crazy if I had to contact my doctor everytime I needed to make a change. I’ve learned more on here and from reading Using Insulin and Pumping Insulin than I have from a doctor. I do believe people on TuD have the combined experience to provide some input to the process, not to tell someone what numbers to use, but to talk about the way to figure that out. But we are all different that way. And if someone were having an ongoing problem, I certainly agree that they should consult a professional.

Yes I have set my pump on my own, so I know what your talking about…I do have experience with a pump.
But everybody is entitled to their opinion but I feel like your putting mine down…sorry that I even commented

My intention was not to put your opinion down, Darlene. I just wanted the OP to know that some of us tweak our own numbers and not to feel she was wrong for asking our advice. Some of us rely more on doctors and some of us don’t. Doesn’t make one way wrong and the other right.

Okay forgive me I understand what you are saying…I guess I took it wrong

No problem, I come on a bit strong at times!

Is all good…have a good night