hacking Accu-Chek Aviva glucose meters to allow expired test strips?

[ixfd64]

My family is very nutritionally conscious, and we often test our blood sugar after a large meal. However, we have a few boxes of expired test strips that our Accu-Chek Aviva glucose meter would not process. The strips weren't cheap, so we don't want to throw them away just yet. The date-checking seems to be handled by the firmware, so I was wondering if was possible to do one or more of the following:

1. Change the internal date on the meter.
2. Hack the meter so it will accept expired strips.
3. Change the expiration date on the strips.

Thanks!

[XOIIO]

Are there electrical contacts on the strips? Some pictures of them, maybe the model number of them and the meter would help.

[mazurov]

Why don't just estimate sugar content by eye? Gives you the same accuracy as incorrect analysis.

[babysitter]

The expiry date specifies how long roche guarantees that the glucoseoxidase is fine - that is a enzyme that gives a reaction with glucose that can be simply measured electrically. And this stuff get spoiled, really, its not a joke. So, hacking this will give results that will be even more off than good ones.

[XOIIO]

The expiry date specifies how long roche guarantees that the glucoseoxidase is fine - that is a enzyme that gives a reaction with glucose that can be simply measured electrically. And this stuff get spoiled, really, its not a joke. So, hacking this will give results that will be even more off than good ones.

Well that sort of settles it, I figured there might be something that actually expires in them, but beyond that didn't know how they worked. Still would be neat to see how they get the date though.

[PA0PBZ]

After a bit of googling:
http://www.diabetesforums.com/forum/topic/45871-how-to-bypass-accu-check-aviva-code-key-and-date-check/

But is using expired strips really what you want to do? 

[edavid]

The expiry date specifies how long roche guarantees that the glucoseoxidase is fine - that is a enzyme that gives a reaction with glucose that can be simply measured electrically. And this stuff get spoiled, really, its not a joke. So, hacking this will give results that will be even more off than good ones.

The rated life has to cover worst case conditions of storage temperature and humidity.  If the strips are stored properly, they will last longer.

Anyway, it's easy to test the old strips.  Once  a month or so, compare the expired strips to an unexpired strip, and see if they are bad.

[scientist]

Why not just read the sugar content if the foods you're eating? It doesn't seem reasonable to do blood sugar testing unless you're diabetic. Take heed of what mazurov and babysitter have said - if you use expired strips you might as well be pulling the blood glucose number out of a hat.

If you're doing this glucose testing because of a site like this telling you to, I'll have to strongly urge you to stop. Most of the "nutritionally minded" people out there who voluntarily do blood glucose testing don't even understand what the point of it is.

Insulin is released by your pancreas after meals to bind up glucose intoawe certain skeletal and fat cells for buffering, not for use; this is something that many health nuts simply don't get. They think cells can be "saturated" with glucose and that that is a cause for diabetes.

Blood glucose levels have to be maintained at a certain level or your cells will simply die. Think of it like this: insulin and glucagon (blood glucose raising hormone) function like a bypass capacitor in a large circuit, decoupling blood glucose levels from food intake. Unless you are literally diabetic or you drink 6 liters of Pepsi daily, you do not need to worry about this.

_{it's also illegal to use medical supplies in a manner inconsistent with their labeling so you're probably breaking the law}

[scientist]

The expiry dated specifies how long roche guarantees that the glucoseoxidase is fine - that is a enzyme that gives a reaction with glucose that can be simply measured electrically. And this stuff get spoiled, really, its not a joke. So, hacking this will give results that will be even more off than good ones.

The rated life has to cover worst case conditions of storage temperature and humidity.  If the strips are stored properly, they will last longer.

Anyway, it's easy to test the old strips.  Once  a month or so, compare the expired strips to an unexpired strip, and see if they are bad.

If only measuring enzyme degradation was that easy...

If the strips are expired and ixfd64 bought them before the expiration date, he/she should take this opportunity to learn that not all expiration dates are created equal. Would you use an HIV testing kit that expired a year ago?

[edavid]

The expiry dated specifies how long roche guarantees that the glucoseoxidase is fine - that is a enzyme that gives a reaction with glucose that can be simply measured electrically. And this stuff get spoiled, really, its not a joke. So, hacking this will give results that will be even more off than good ones.

The rated life has to cover worst case conditions of storage temperature and humidity.  If the strips are stored properly, they will last longer.

Anyway, it's easy to test the old strips.  Once  a month or so, compare the expired strips to an unexpired strip, and see if they are bad.

If only measuring enzyme degradation was that easy...

Either the strips are still accurate, or they are not.

If the strips are expired and ixfd64 bought them before the expiration date, he/she should take this opportunity to learn that not all expiration dates are created equal.

What do you mean by that?

Would you use an HIV testing kit that expired a year ago?

How is that relevant?

[poorchava]

 

Man, I'm really all for hacking, reusing stuff, saving money when you do need to spend them and all that, but deliberately using expired consumables for this kind of device if just plain fuckin stupid. Don't do this.

Would you take a medication that has expired?

[babysitter]

Scientists enzyme degradation comment might have meant that it certainly isn't just a simple % error per month thing. This stuff behaves a bit strange when compared to most school chemistry reaction speeds.

First off, those test strips have really wide error margin allowed, iirc somewhere near 20% +/- of reading at the "healthy" level that is to be expected and even more error in the very low and very high concentrations (reading the instructions will tell you), where you only need to be alarmed and it doesn't really matter exactly how bad it is, maybe ?
 
No one prevents you from mixing up some calibration fluid with a known glucose content and compare the measurement results of fresh and expired strips.

You might assess the risk to for yourself and decide that the error is not a threat as your blood sugar regulation system works well, then go on and use the strips with the known hack whose existence I consider due to the link posted above.

Hint: Your (healthy) blood sugar level reading is the output of a already regulated and compensated system, so it doesnt mean a lot to begin with... I would like to add something to the large capacitor of scientists model: A voltage regulator with source and sink capabilities

May I point you to lactate measurement? This stuff is way more interesting, a rise when in rest is always a bad sign...

[SeanB]

You can buy a set of test solutions for the strips, but then this also has a definite expiry date, and can only be used **ONCE**, as it reacts with oxygen once opened.

I simply changed to the No code (Bayer Countour 2S)  meter, and as a bonus the strips are as accurate ( I compared the results when doing a test at the lab which used another old Accucheck and a GCMS measure if needed) and about half the price of the Accucheck ones.

I took the old Accucheck apart, and it is very compact, and has 2 soldered in lithium batteries in addition to the CR2032 main replaceable cell. the code is actually a simple I2C eeprom, probably easy to reprogram if you want.

[Stonent]

Accuracy and everything else aside, could it be as simple as changing the date on the meter?

[SeanB]

You cannot change the date and have it work, unless you have never used that pack of strips in the meter before. the unit stores the serial number of each code chip inserted in internal memory. As it has an internal flash it probably has enough space to store hundreds of strips. It stores the reading as well, for pretty much every test as you can scroll back pretty far.

[ixfd64]

The strips expired fairly recently, so I don't think accuracy is that much of an issue.

This is a little off-topic, but for the record, some drugs can last a long time after the "expiration" date: http://www.cnn.com/2012/10/08/health/throwing-away-expired-meds

[scientist]

Note the "some." Here is a far more authoritative source that doesn't demand to be judged by Betteridge's law.

Just as many drugs will degrade into something actually toxic.