# target ranges on the roche accucheck combi pump



## Dory (Mar 10, 2013)

Hi all,

I've noticed a trend on my pump concerning the target ranges that accompnay each time block i have for my bolus/CF ratios.  at the moment they are as follows:

00.00-09.00: 1:8 bolus ratio, 1:1.6 CF ratio, target range 5-7mmol
09.00-15.00: 1:7 bolus ratio, 1:1.6 CF ratio, target range 5-7mmol
15.00-00.00: 1:8 bolus ratio, 1:1.6 CF ratio, target range 5-7mmol

I've noticed that during the first two time blocks, any correction it calculates is to take me back to a target of 6mmol.  this is normal for the accuchek pump, as it always attempts to correct you back to the mid point of your target range.

....EXCEPT....at some random points throughout the day, I've noticed that any CF it gives me is to take me back to 7mmol.  Which is clearly not what it is doing on other occasions!  I'm having to manually work out the extra CF i need on top of what it suggests and add it to the suggestion CF dose.  It can't be any IoB/active insulin, as I've checked when it underestimates and the active insulin levels are showing as 0.0 on the screen.  In fact, on some occasions, it even underestimates WITH IoB.  for example, last night at bedtime:

23.50: 10.9mmol
active insulin remaining: 1.0u.  
No carbs eaten.
recommended CF dose: 1.4

according to the above (ie IoB+CF) and using the CF ratio of 1:1.6 that I'm on, that would bring me down 3.9mmol, ie down to 7mmol.  Buy accuchek apparently brings you to the middle of your target range, so for me the meter should have worked the maths out to bring me down to 6mmol (as it was, I manually worked it out and ended up giving another 0.6u on top of the 1.4 it suggested; hence a perfect reading this morning of 6.0mmol).

I have noticed that also the calculator sometimes doesn't suggest a correction to bring my reading within the target range (ie one night, the active insulin was showing as 0.0 and the correction it suggested would have brought my reading down to 9.0mmol - nowhere near my target range!!)

The question I'm asking is: has anyone else noticed their Roche pump correcting to different points in the target range other than smack bang in the middle?  I'm worried that my equipment is reaching the end of its life and needs changing (even thoug the meter is under 3 years old as it's a replacement for the original).

The other alternative (and this is something that was discussed in a separate thread by Mike and Tropywench) is regarding what the pump considers as active insulin.  We've already worked out that the figures shown in the 'active insulin' field only reflect CF bolus and not any food bolus.  BUT what I have noticed is that the underestimated CF suggestions my meter is suggesting (when there's a '0.0' in the active insulin field) seem to come after i've had a food bolus.  SO......it's almost like it's taking the food bolus into account when suggesting a CF, but it's not showing the remaining food bolus in the active insulin field.  This is even more worrying!

thoughts guys?


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## Pumper_Sue (Mar 10, 2013)

Haven't read all through your post as brain tired today. So probably misunderstood what you are saying asking.
Simple solution is change your correction factor for the different times of day if you are not on target, and your basal is correct.
A pump will not be faulty as you discribe.


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## Dory (Mar 10, 2013)

sue - thanks but think you need to re-read my post later on...

the meter is not correcting to the numbers I'm asking it to


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## trophywench (Mar 10, 2013)

I know what you mean but I don't notice it regularly probably because as I don't do very much regular exercise (I mean it's sporadic so I make adjustments at the specific time rather than have it programmed in, or even have a set procedure for it) so things are usually pretty straightforward and fairly simple for me now.

I did get quite a lot of glitches like this a while ago so what I did is gonna sound ridiculous and it shouldn't do - in fact anyone would say it can't possibly - but it worked.  Madness.  

Make your ranges eg 5.5 to 6.5, or 4.8 to 7.2 - or any other two numbers different from the original where smack in the middle of them is THE number you want to be.  Just changing it for the sake of it, is all it seemed to take.

I wondered if it's summat to do with - like predictive text, where it gets fixated on predicting one word all the while once you type in a C or whatever, no matter how much of the real one you accurately input - or something?  Clueless.

Unless anyone knows the real answer to this fascinating question LOL


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## Dory (Mar 10, 2013)

hi TW,

yes somehing random like doing what you've suggested may re-set it!  seems odd but as the machine is being odd anyway, fight odd-ness with odd-ness!

thanks!


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## ypauly (Mar 10, 2013)

I think that late night adjustments maybe  accounting for you going to bed so aims for the hihher end of your target so that you don't hypo in your sleep morning djustments may just take you to midrange.

I may need to read again too lol.


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## trophywench (Mar 10, 2013)

That may explain some of mine Paul, that hadn't struck me.

God - I wish I could teach my brain to be more analytical.


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## Dory (Mar 10, 2013)

wel that's what i thought both....but surely the machine can't be that intuitive?  surely it simply works off an algorithm that says at XXX times these rations YYY and ZZZ are functioning.  After all, that would require the programmers to somehow programme into the machine that between the hours of AAA and BBB a human is asleep - which I don't think they would do as this is too proscriptive and they'd be inundated with people saying 'i work shifts that's not correct' or 'i don't sleep during those hours so that's not correct' etc etc

plus it's not just at bedtime, this happens occasionally through the day too, ie anytime from lunchtime through to 9pm.

so baffling!


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## Northerner (Mar 10, 2013)

Dory said:


> wel that's what i thought both....but surely the machine can't be that intuitive?  surely it simply works off an algorithm that says at XXX times these rations YYY and ZZZ are functioning.  After all, that would require the programmers to somehow programme into the machine that between the hours of AAA and BBB a human is asleep - which I don't think they would do as this is too proscriptive and they'd be inundated with people saying 'i work shifts that's not correct' or 'i don't sleep during those hours so that's not correct' etc etc
> 
> plus it's not just at bedtime, this happens occasionally through the day too, ie anytime from lunchtime through to 9pm.
> 
> so baffling!



Have you reported it to Roche? It may be a known problem. As a programmer in a former life I have come across the most glaring of errors for situations the programmer clearly never envisaged and never tested fully.


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## Dory (Mar 10, 2013)

yep, will have to give them a call tomorrow alan and see what they have to say.  will keep you all posted!


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## MaryPlain (Mar 10, 2013)

I don't use the combi pump but I do have an expert meter, which I believe is the same as the one that comes with the combi pump to all intents and purposes.

I've also noticed that it doesn't suggest a big enough correction factor to bring me to my target at bedtime - the correction it suggests is just to the top of my target range. I think that is built into the algorithm and agree that this is far too inflexible.  I have set my ranges very small to minimise this effect, although I don't make great use of my expert meter having managed without it for several years and finding it far too much of a chore telling it how much I'm eating etc.

I agree that this is not a fault of your pump, but could be a fault of the meter, if the answer that's been suggested doesn't account for all the anomalies! However I imagine it's a design fault rather than a fault with your particular meter.

I'd be very interested in the response you get from Roche - but I wouldn't hold out a lot of hope that you'll get to talk to someone who really fully understands it! 

I took part in the market research testing for this device before it first came out, and the instructions contained some errors which demonstrated to me that whoever wrote them really didn't understand how the meter worked!


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## everydayupsanddowns (Mar 11, 2013)

Dory, I notice on another thread that you are a bit of a grazer... Is it connected to the delay that the Combo/Expert uses to avoid stacking. Can't remember what it's called, not meal rise (though that would also reduce corrections) and not insulin duration, but the other one... acting time? Basically the period before you respect your BG to fall. Along with the meal rise these could bothe be reducing the corrections the meter will suggest if you are eating/injecting close together I think

EDIT: just looked it up. The setting I was thinking of was 'offset time'. When boluses are given close together (within the acting time set for the insulin) AFAIK the initial correction/meal bolus is assumed to be working perfectly and additional correction is only calculated on the BG value over and above meal rise/offset time parameters to avoid stacking (p99 and p100 of the big Expert 'training handbook'). I suspect these factors are at play in the behaviour you are seeing?


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## Dory (Mar 11, 2013)

god Mike - you could have it there - the meal rise limit.....

just checked and that seems to add up - my target is 5-6 (ie 6) and my meal rise is 3.0mmol.  all the corrections are looking to correct to 9mmol......

my acting time is 4 hours.  So basically the settings are currently allowing my reading to go as high as 9.0 for hours hours after every single thing I eat and bolus for!  Not good for grazers as that effectively means if I'm over 9 it will only ever correct to that!

That also means the settings are programmed so that the meal rise can be allowed for as long as your acting time (ie 4 hours in my case).  Which isn't really a very good setting  - after all meal rise limits should really only be valids for up to about 2 hours after I eat!  

Huge programming error!  Question is, should I reduce my acting time to 2 hours (to allow a 'proper' correction after 2 hours of eating) or should I reduce the meal rise limit to 6.0mmol (which kind of ruins the purpose of the function!)?????  hmmmm....


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## Dory (Mar 11, 2013)

ps as a perfect example, last night:

9pm - 11.4mmol, active insulin 0.0u, suggested CF 1.5u - which would have brought me down to 9.0mmol.

I had eaten 40g of carbs at 7.45pm, 1hr15 mins before hand......


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## trophywench (Mar 11, 2013)

And what IS your Offset Time set at? - mine is 1 hour?


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## trophywench (Mar 11, 2013)

I await the outcome of your conversation with Roche!


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## Dory (Mar 11, 2013)

Hiya TW,

I was recently told by my DSN that the offset time was the time taken for *all *the insulin you have injected/pumped to be completely active, so have that set at 2hrs (as per DSN's advice that it takes 2hrs for humalog to be 100% active and being used).

Just about to phone Roche now.....


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## Phil65 (Mar 11, 2013)

Dory said:


> Hiya TW,
> 
> I was recently told by my DSN that the offset time was the time taken for *all *the insulin you have injected/pumped to be completely active, so have that set at 2hrs (as per DSN's advice that it takes 2hrs for humalog to be 100% active and being used).
> 
> Just about to phone Roche now.....



Keen to know their response.....i have the same issues!


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## Dory (Mar 11, 2013)

right, just had a chat with 'Stephanie' from Roche.  very helpful lady.

Essentially, Mike has hit the nail on the head.  Any CF doses done within the acting time you have programmed into your meter will only correct to the upper limit of your meal rise.  So if your target is 6mmol, your meal rise is 3mmol and your acting time is set at 4hours, and you test 3h59mins after eating/bolusing and your reading is 11.0mmol, the mater will calculate enough correctional to bring your reading down to 9mmol, NOT 6mmol.

I explained that isn't helpful for grazers who eat little and often within the hours of the acting time, as your pump is therefore always assuming that it only needs to correct to your meal rise limit.  She agreed with me and even said it was a little ironic given the pump was designed to allow that freedom to eat little and often if you wanted to!

She said she wasn't aware of any options to unlink the acting time and meal rise, her only suggestion was that i might want to turn off the meal rise limit function which is what other users do.  She did however promise to pass my feedback on (maybe this will affect future productions, who knows).

I also raised the issue of the phrase 'active insulin' on the bolus calculator screen (ie wher eit tells you how much insulin you have left in you).  She also confirmed that this was what Mike and I (and others) believed - namely that this only refers to CF doses, and not meal bolus insulin.  The reason given was that the machine assumes that any insulin you give for food will be used directly up by the food item you are eating, therefore ther ewill nto be any 'leftover' to count as 'spare' insulin that would cause insulin stacking.  That kind of makes sense.  Howeve rI have told her that if that is the case, the screen should be clearer marked to that effect (ie to say 'active corectional insulin' or something along those lines).

So in short, no solution other than not allowing for a meal rise (begs the question why have that option then Roche?)......


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## Dory (Mar 11, 2013)

frustratingly, I have just tried to set my meal rise limit to 0.0mmol and the lowest it will go is 2.8mmol!

So i will constantly have to manually work out CF doses from now on!!  

HOW UNHELPFUL!!!

EDIT: unless someone knows how you turn that specific bit of bolus advice off on the Roche pumps??


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## Phil65 (Mar 11, 2013)

Dory said:


> frustratingly, I have just tried to set my meal rise limit to 0.0mmol and the lowest it will go is 2.8mmol!
> 
> So i will constantly have to manually work out CF doses from now on!!
> 
> ...



....in the same boat!.....but used to it now, although irritating!


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## Dory (Mar 11, 2013)

on the phone to them now to see whta can be done about this (if anything)


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## everydayupsanddowns (Mar 11, 2013)

Dory

Since part and parcel of this involves the 'active time' and 'offset time'(in terms of when it will allow/deny more correction) I suppose you *could* artificially shorten those such that it gives you the correct advice more often than not.

I did this myself over the first year I used the Expert. I expeerimented with giving the device the numbers *it* needed to give me good advice (whether or not I believed that whatever that factor was actually acted over that period in general terms). ISTR I set my 'offset time' to the minimum - 45 mins, and had an artificially short 'active time'.

I also completely ignored 'active insulin' as it was of no use to me really the way they had configured it.


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## tracey w (Mar 11, 2013)

Wow you guys are blinding me with science! Had to read al again. Now I get it,I think? Checked my meal rise 2.8 acting time 4 hours, offset time 1 hour

I must admit for me I don't think too deeply as will it get me to mid range, perhaps I should. But I always always think, when did I last eat, grazer too. And I always think nah that will be too much or I need a bit more than suggested, or if I correct at all I will hypo due to stacking, seems to work fro me. You have all made me think a bit more about it though.


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## Dory (Mar 11, 2013)

Tracey I think you have to go with what works for you.  so if your guesstimations are working then great, no need to worry about the science bit! 

for me, I'm one of those annoying people that likes to know the whys and wherefores of everything!


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## trophywench (Mar 11, 2013)

What a bummer!

No, the only option is upwards, we are stuck with 2.8.

I'll try and check the Manuel tomorrow, but not promising, got a bit on tomorrow esp if the 7 pallets of paving slabs arrive!


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## Dory (Mar 12, 2013)

I have several healthcare professionals i could do with making disappear TW 

I was going to leave a reply until Roche phoned me back yesterday.....but they didn't!  They last I spoke to the chap though he did mention that there may be an option to make the individual change to the meal rise limit on the accu-chek 360 software - the version that healthcare professionals use, NOT the standard 'diabetes management' software that pump users get (and I've got).

But he wasn't sure and was going to check and call back....which is what I'm still waiting for.....


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## Phil65 (Mar 12, 2013)

Dory said:


> I have several healthcare professionals i could do with making disappear TW
> 
> I was going to leave a reply until Roche phoned me back yesterday.....but they didn't!  They last I spoke to the chap though he did mention that there may be an option to make the individual change to the meal rise limit on the accu-chek 360 software - the version that healthcare professionals use, NOT the standard 'diabetes management' software that pump users get (and I've got).
> 
> But he wasn't sure and was going to check and call back....which is what I'm still waiting for.....



....this is what they said to me Dory, I think I have the software.....I need to get on to this...will let you know how I get on


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## Dory (Mar 12, 2013)

ooh yes please let me know Phil.  They said it wasn't the 'accu-check 360 diabetes management system' but the other one (can't remember the name now).


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## Dory (Mar 12, 2013)

Hi all, I finally had a call back from one of the senior technicians at Roche about the issue above.  I explained that linking the meal rise to the acting time (at 4 hours for some of us) was not replicating what happens in rea llife, as in real life you'd expect any meal rise to start decreasing after about 2 hours.

She then helpfully explained that the 'snack size' function played a key part in all this.  If you eat something over your snack size limit, any correctional doses within the acting time period will correct to your meal rise.  HOWEVER (and this I didn't know) - if you eat something under your snack size limit, then have to do a correctional dose within the acting time of that snack, the the meal rise is not taken into account and it corrects to your target range.  Eg:

acting time 4 hours
target 6.0mmol
meal rise limit 9.0mmol
snack size 10g CHO

in the above scenario, eating a 15g CHO snack at midday, then testing at 3pm and finding your bG is 12.0, will mean the meter corrects to 9.0, rather than 6.0

IF however, you reset your snack size to 20g and apply the same situation above, the meter will suggest a correction dose to bring you down to 6.0.

This is news to me (when I got hooked up, I was told that the snack size was to let the machine know how many CHO you eat without needing a bolus) but really helps, as essentially when I graze i eat a banana, yoghurt, apple, basically stuff 20g CHO or less.  So I have change my snack size on the meter to read 21g.  That means that when I have a medium sized banana at 8pm (20g CHO), and test before bed at 11pm and my reading is higher than it should be, then THEORETICALLY it should correct to 6.0 rather than 9.0.

So, in short: 

- if a high bG reading within acting time and last food bolus was larger than snack size = a dose that corrects to meal rise limit.
- if a high bG reading within acting time and last food bolus was smaller than snack size = a dose that corrects to target.

Hope that makes sense!  She also advised me that even if I get my renewal tubed pump in Nov 2013 (ie at the 4 year marker) I will still be eligible for hte patch pump when that gets released and it won't cost ant extra to PCTs (quite how they worked that out I didn't bother to ask).


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## tracey w (Mar 12, 2013)

Ok,must admit am intrigued. My snack size is 10cho

Would it benefit me to raise this to 20cho in order for corrections to be within my target range? I'm always wanting control to be tighter. I may guesstimate ish but its always based on what I know I need or don't. I think it explains why sometimes I need to correct more than meter is telling me too. I always take factors such as activity,exercise etc into account too.  If I just pressed the bonus button to what it tells me this wouldn't work for me.

I mean bolus !


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## trophywench (Mar 12, 2013)

I've never entered anything in snack size cos my BG's that boring, if I eat 5g carb I'll get a commensurate increase in BG, which is not to say I don't sometimes eat a snack and think Oh $od it and not bolus.  So my snack size is Nil.  But no meal bolus for me is ever going to be less than a snack one.  

My brain No Funcione; where does that leave me? - correcting to pre-meal test level plus 2.8 meal rise, or top of time block range, or top of time block range plus 2.8; or what?

Yrs confused,
Bedworth


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## Dory (Mar 12, 2013)

Tracey - if you're having hte same problems I am (ie you're noticing it's not suggesting enough correction bring you within your target) then you might benefit from changing your snakc ize, yes.  I guess you can only try and see if it works.

TW for you, and going on what the Roche lady told me, I think that because you have no snack size, any food you bolus for would count as a meal and thus if a CF was needed within your acting time, it would take you to your meal rise limit.

But don't quote me on that!


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## Dory (Mar 12, 2013)

well i have just checked my bG level after changing the settings earlier and the CF dosage it's now suggested (90 mins after a 'meal' of 40g CHO) is to bring it down to my target (ie not my meal rise limit).

So that seems to have solved the trick


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## trophywench (Mar 13, 2013)

I was thinking of a sback late this afternoon and was gonna try it but when I tested it turned out I was flipping hypo.  Can blame the double glazing salesman at the door I couldn't get rid of for making the hypo be 2 point summat instead of 3 point summat which I'm sure was all it was to begin with.

And in hindsight, we had different bread to normal today and so I checked the package and bolused for lunch on what it said which is always 2 slices = c 35g, but I SHOULD count it as 30 because that's what bread always is for me at lunchtime notwithstanding the packet.  Yes I did suspect my carb ratio at lunchtime but any other sort of carb behaves normally.  I'm weird .....


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## Dory (Mar 14, 2013)

never mind TW - always another chance (the joy of D!)

as it turns out, I had a stupidly high reading of 20.2 @ 9pm last night.  using the new dosage with the new snack size setting, I woke up to a 4.6 this morning.  So increasing the snack size from 10g to 21g for me certainly has solved the problem!


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## Phil65 (Mar 14, 2013)

Dory said:


> Hi all, I finally had a call back from one of the senior technicians at Roche about the issue above.  I explained that linking the meal rise to the acting time (at 4 hours for some of us) was not replicating what happens in rea llife, as in real life you'd expect any meal rise to start decreasing after about 2 hours.
> 
> She then helpfully explained that the 'snack size' function played a key part in all this.  If you eat something over your snack size limit, any correctional doses within the acting time period will correct to your meal rise.  HOWEVER (and this I didn't know) - if you eat something under your snack size limit, then have to do a correctional dose within the acting time of that snack, the the meal rise is not taken into account and it corrects to your target range.  Eg:
> 
> ...



Great work Dory! thanks for this.....I've just changed my snack size to 21g....I'll see it how it goes


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## Dory (Mar 14, 2013)

Hope it helps Phil - let us know how you get on!


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## christine.h (Apr 3, 2013)

Mine does the same about 2 to 3 hours after last meal the bedtime one does not give a CF I have put my own CF in at times but lately I have not and it has dropped on its own accord


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