Type 2 Glucose monitoring strips and storage temperature

[DJC3]

I started a new pot of SD Codefree monitoring strips 2 days ago and have had surprisingly high readings since then.
Last night after dinner I was 9.7 the highest I’ve been since starting LCHF. I put this down to a slightly carby- er meal than usual, and vowed never to eat it again!

Fbg this morning was 7.9, again the highest it’s been for a few months. I tested again after coffee and a long dog walk - still 7.8

Then out of interest I tested with a brand new pot that had just arrived in the post this morning - it was 6.8
I repeated with strips from both pots and got the same results: the older ones gave readings 1mmol/l above the new ones. ( Running out of fingertips by now)

A bit of sleuthing confirmed they were well within date BUT with a magnifying glass I could see the optimum storage temperature is between 2 and 32C

Ive been keeping these in my bedside drawer which is right next to the radiator, so I think its likely the temperature will have exceeded the max on several occasions. This pot was the last one in my previous delivery so has been in the drawer for around 3 weeks. I think this must be the cause - has anyone else found this?

Ive moved them all to the bathroom cupboard now which is much cooler and think I’ll chuck the old strips out: an expensive waste but I reckon £7 is worth it to stop the palpitations over these unexpected readings.

 

[bamba]

The strips have an enzyme in them which makes them time(date) and temperature sensative.
That's one reason they must stay in you hand luggage on aircraft.
Have you tried using the reference fluid ?

 

[Guzzler]

We live and learn. I am glad you got to the bottom of the mystery quickly.

 

[Bluetit1802]

Ive moved them all to the bathroom cupboard now which is much cooler and think I’ll chuck the old strips out: an expensive waste but I reckon £7 is worth it to stop the palpitations over these unexpected readings.

The bathroom is the worst place for them because of the steam and condensation etc.
Mine are in a drawer in my office, which is upstairs and heated like the rest of the house, but the drawer is not next to a radiator.

Codefree are (or were) notorious for inconsistency between batches (note the word batches, not tubs within a batch) Check the batch number on your old ones and new ones. It gives it on the tub box somewhere. A few years ago there was a very dicey batch that many of us complained about. Home Health looked into it thoroughly, and concluded it may have been because the batch was shipped in cold weather. I ended up throwing away a large number of tubs, but Home Health replaced them (after I had returned some samples along with some data)

 

[Rachox]

I find that the Code Free strips can be variable. During the summer last year I had a batch that read higher, the effect of which you can see clearly on my averages graph, circled in yellow (ignore the blue circle that was the month I had a chest infection, an operation and a steroid jab!)

 

[DJC3]

@bamba @Guzzler @bluetit 1802 and @Rachox thank you all very much for your replies.

Bamba thanks for the tip about handluggage on aircraft - I’m off to Iceland in a couple of weeks and was going to put them in the hold to avoid awkward customs questions, I’ll keep them with me now.

Haven’t tried the ref fluid yet but will do: another good tip. (I’m ashamed of myself, having spent my working life in laboratories this sort of stuff was second nature to me and very rigourously controlled - I’ve embraced retirement and lack of rules a little too enthusiastically!)

The table outside the bedroom door might be the best place then, good point about the steam in the bathroom @Bluetit1802
The batch nos on the 3 pots I received today are the same as eachother but different to the old ones. It’s only the last pot of old ones which has given problems so I reckon it must be the long, often hot storage.

Your graph is really interesting @Rachox ( not to mention very impressive) and as you and Bluetit say there have been inconsistencies before I’ll be on the lookout now.

I’m just so pleased that the bonkers results were probably just that - bonkers and not necessarily diet related.

 

[dipsydo]

I had some accu chek ones which after about the first 10 started reading high , took me a bit of time to cotton on - I bought a new pot of 10 and compared reading taken at same time and consistently the old pot reading was higher so concluded that just opening the old pot had caused the issue ( had the same issue another pot from same batch) complained to Roche but did not get far - at least your code free were cheaper ! My view is that I use meter reading as a guide and not gospel so will show if going up or down and try and not to get too concerned as even "bad" strips will show if a spike or not

 

[Bluetit1802]

I wonder with strips that come loose in pots, rather than wrapped individually in foil or in cassettes, if opening the pot on a regular basis must cause a slight deterioration each time they are exposed to the atmosphere. The nearer the end of the pot, the less reliable they may be. Just a thought.

 

[Deleted member 308541]

The cupboard in my office at home where I keep my spare strips in is about 25° all year round.

The tub that is in use in the meter bag varies with what ever the ambient temps are between upstairs and the office, which is at 27° at present.

Abbot Freestyle lite strips min / max storage temps are are 3° and 30°.

 

[DJC3]

My view is that I use meter reading as a guide and not gospel so will show if going up or down and try and not to get too concerned as even "bad" strips will show if a spike or not

Good point. Darn it, have thrown the whole pot out now but If it happens again I may just stick with it. Thanks

 

[DJC3]

I wonder with strips that come loose in pots, rather than wrapped individually in foil or in cassettes, if opening the pot on a regular basis must cause a slight deterioration each time they are exposed to the atmosphere. The nearer the end of the pot, the less reliable they may be. Just a thought.

Another good point!

I guess the only way to be sure is to run the ref fluid at the beginning and end of the pot. But we know these monitors aren’t 100% accurate anyway, and I go through a pot a week so hopefully that’s too quick for much variation.

They seem happy in their new home now: hope they’ll be comfortable.

 

[Deleted member 308541]

I go through a pot a week so hopefully that’s too quick for much variation.

I am the same, I go through fifty strips a week.

It has never occurred to me about the strips deteriorating though, as I have forgotten to snap the lid back on at times.

 

[jos64]

I’ve had some high readings which confused me as I have been careful with carb intake. The last 2 occasions I have retested straight away and the reading is closer to what I would expect. This also seems to be when I don’t get a good droplet of blood. No expert as only diagnosed 2 weeks ago but learning fast the forum is a great help , so thank you all

 

[Bluetit1802]

Another good point!

I guess the only way to be sure is to run the ref fluid at the beginning and end of the pot. But we know these monitors aren’t 100% accurate anyway, and I go through a pot a week so hopefully that’s too quick for much variation.

They seem happy in their new home now: hope they’ll be comfortable.

The control fluid only tells you if the meter is working properly. ie reads between plus and minus 15%.

 

[Richard Frost]

I test every New pot with the standard test
That they sell low 2.5 high 17.6 or something like that. keep my pots in study a little room that dose not change in temperature alot

 

[TTTE]

All this discussion about rest strip storage etc has me worried. I expect like most of you I have a small wallet that my BG monitor, strips, Lancet and record book etc all live in. I take this with me to work so it goes from my room to an air conditioned car where it stays until I test during the day and then at end of shift it goes back to my room. This subjects it to a lot of temperature changes throughout the day.

Then once a month I commute home to Malta. I only have a hand luggage bag and my kit goes in that. Sometimes the cast of the Muppets, sorry airport security ask me what it is, but have always always always accepted what I tell them, I have never been asked to demonstrate it.

At home temperatures vary wildly between highs in summer of about 3°c to lows of -17°c in winter, sorry that's SE London where I work. Malta varies between 12°c in winter to 30+°c in summer. Generally my kit stays in the dining room where it is pretty cool, but if we go out tgen again it is subject to wildly varying temperatures.

I just assumed that incidental high readings were down to me being new to being diabetic and I'm still learning to get to grips with the condition

 

[BloodThirsty]

I am the same, I go through fifty strips a week.

It has never occurred to me about the strips deteriorating though, as I have forgotten to snap the lid back on at times.

Just the other day someone on this forum (regretfully I've forgotten who) suggested that when a new pot is opened 10 strips at a time are decanted into a second pot for daily use.

A nice simple idea that reduces the number of times that strips are directly exposed to ambient conditions. Should the environment become detrimental only 1/5 of a pot is potentially affected.

Hat tipped to unknown author.

 

[Bluetit1802]

A couple of years ago when I complained to Home Health about the inconsistency of my Codefree meter, one of the questions I was asked is how and where I store my strips. He told me many people decant strips to a tupperware box, or store them in a bathroom, and these actions cause strip errors. They should be kept in the original tub and well away from a steamy bathroom. I suppose decanting to anotyher Codefree tub is OK as long as the lid still snaps shut.

 

[Mr_Pot]

The control fluid only tells you if the meter is working properly. ie reads between plus and minus 15%.

Actually I think it is worse than that. The TEE2 tub I have here says Control A 5.9 - 8.8 which is a +/-20% range so would only show up a gross error.