GlucoRx system

H.

We have had to remove your link to the Company as it is a Commercial link which is not allowed.

This has been mentioned before in a thread about the withdrawal of test strips........

viewtopic.php?f=1&t=14872&start=30#p154711

Transgression......nah ! You should see what some others get up to....... :shock:

Anyway, here is the review from this websites Community pages......nobody has commented there either ? Basically, if it does what you want etc.....meters are pretty much the same, accuracy is always + or - 10% according to EC regs.

If you have to pay for your own strips then it might just fit the bill.

http://www.diabetes.co.uk/blood-glucose ... meter.html

I've just been testing the consistency of the GlucoRx versus the OneTouch Ultra and I've found a significant variation in the GlucoRx. Testing the same site twice on the Rx gave significantly different values, like 7.5 and 9.8, when at the same point my OneTouch Ultra gave 6.5 twice - I used the same drop of blood to feed two strips, one for each meter.

I've found that the Rx consistently gave a higher reading and the stated accuracy on their website seems to be no more than ± 20% which I think is enough to be misleading. Certainly if you are trying to follow a low or reduced carb diet and want to make sure you are avoiding post-meal peaks, the Rx might give you misleading information.

Over a period of one week (twenty readings), I never once found the Rx giving a lower value than the OneTouch and the range of differences between them was from 0.5 mmol/L to 3.5 mmol/L. I tried to find some references for trials of these meters and only found the OneTouch at: http://www.ncbi.nlm.nih.gov/pubmed/14709195 which demonstrates a high level of accuracy.

I'd be interested in any link to a comparable trial with the Rx. At the moment, I'm keeping the Rx as a not very trustworthy backup. I could just have a duff one but I worry about that ±20%. On a reading of 7.0 that could be anywhere between 5.6 and 8.4 - a reading of 9.0 could mean 7.2 up to 10.8 which is a massive uncertainty. The strips are certainly cheaper but it's hard even to argue that the Rx measure of a trend would be accurate since each reading could vary by ±20%. Any trend seen might not even exist.

I'd be interested in hearing of other folks' comparison tests for these meters.

There are many threads about meter accuracy on the Forum.........here's just one :

viewtopic.php?f=15&t=12663&p=116298&hilit=meter+accuracy#p116279

Any meter manufactured for use in the EU has a CE mark which applies to the Medical Device Directive 93/42/EEC. The product meets the requirements of EC Directive 93/42/EEC. I understand it is a Class I device and has a less stringent standards allowed than a Laboratory analyser would have (Class III).

There are also more recent meters which read in Plasma equivalent from a Whole blood sample and older meters which read in whole blood samples so there will also be a difference in the numbers. Not sure what your particular meters are.

This from just one NHS Trust document........

Glucose meters are intended for monitoring the patient's treatment and are approved by the
MHRA only for this application. Laboratory results must be used as the basis of diagnosis and
determining appropriate treatment. Diagnostic cut-offs (e.g. WHO criteria) are defined with respect to laboratory analysers which have very little variation in results between manufacturers.

Glucose meters will not give the same values and there is often considerable variation between results for the same sample analysed on different meters.

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We always recommend members to only use one meter for any readings and not to double test even from the same drop of blood. There are many variables which would affect any readings taken in such a way.

They are not 100% accurate, they are only a guide. I wish they were more accurate but apparently this is all down to cost as one Rep once told me. They could make meters which were probably 99% accurate.........however, the cost would be prohibitive and they certainly wouldn't give them away for free !

I use the Lifescan OneTouch UltraSmart and the UltraEasy meters but never compare them. They seem to reflect my actual feelings when either high or low and that's good enough for me.

So, one meter, one test........saves an awful lot of stress and confusion. :|

Thanks for the link to one of the other discussions.

Of course, there's an error range associated with each meter and although they're probably OK for identifying large values one way or the other, they won't reliably help in identifying trends, ie if you are gradually reducing your levels, even if you stick to one meter. It might make you feel less worried, but it won't necessarily give you readings which are consistent with themselves.

The error of ±20% means that the meter won't even be consistent with itself because you won't be able to tell if your downward trend exists. The point is that only if the meter is consistently biased in one direction or the other will the values be indicative of a trend and if that was the case, the accuracy would be better than ±20%. Otherwise, the errors will be spread out, without any way of knowing the distribution.

Testing often at the start of a programme to reduce BG means surely that we ought to try to use something which is more reliable than the ±20%, otherwise we can't trust those many readings we are taking. It's a good motivator to measure the BG but perhaps we shouldn't place too much reliance on it and treat the A1c as the important measure.

I appreciate that for forum managers this must be a pretty tedious topic but if we are advised to test often to get control of the BG levels but some of the meters are no better than ±20%, it's possible to end up carefully watching numbers that contain a very large uncertainty, and sometimes they will simply be wrong.

If there are any controlled trials for these meters out there I'd be interested in any links. At the moment, the best data I've seen is for the OneTouch. I'm interesting in specific tests of accuracy in controlled circumstances. Thanks.

Meters are always a source of discussion here, sometimes quite heated. No matter how many times we tell people they are only a guide there are always those who want them to be more accurate. Not a bad thing and I subscribe to that thinking personally. However, they aren't, they are built to an approved specification. If people don't like the spec they are built to then they should take it up with the manufacturers as I once did or even the EC who give approval to these monitoring devices.

If you wish to have something which is as accurate as a laboratory analyser.....then be prepared to shell out thousands of pounds because that is what it will cost you ! There is then the upkeep and testing of the equipment which also would have to be factored in.

The plain fact is we, as Monitor's on this Forum don't like to confuse new members who are already confused enough as it is by implying that the meter they are using is of little use. If that was the case why do we bother telling them to test, test test ? They are perfectly adequate for the purpose. I have been using a meter of one sort or another for 14 years and I have never been let down or misled by ANY meter even the cheapest ones.

A meter is only as good as the person using it. If they have no idea what the readings mean then it is pointless them even thinking of using one.

I have a OneTouch UltraSmart meter with built in graphing capability. That shows all the data and the trends. Everything I need to know.

The HbA1c is an accurate test over a period of 3 months and does show the trend, upwards or downwards. However that is only an indicator that the Bg levels are either on the way up or down.

The only sure way to know what your Diabetes control is like on a daily basis is to test using your meter (one meter) frequently. Note the readings down if you don't have a meter like mine. Even if they are not 100% accurate they still give you more information and will indicate what your control is like at the time you take a reading. Who wants to wait till 3 months have passed before knowing if your Bg levels are good or not ? I prefer to see what is happening NOW and react to those readings, even if they are not 100% accurate. They are as accurate as we can have for now. I work with what I have in front of me not what I would like to have in front of me.

As for your research and data links. Not something I have, sorry. Not really been interested in that aspect. They are all built to EC spec and we know from experience that some seem to be more accurate than others........however I and those in the medical profession who use these self same meters in Hospital settings rely on them. We also know their limitations. As I previously posted, in a Hospital they would double check with a Lab test if they had readings which were of concern. We are not in that position as we are just 'monitoring' our own levels.......not using them for diagnostic purposes. They are just a guide.......nothing more.

Any meter is a useful tool together with how you feel...they simply are NOT precision instruments.

There is an interesting review article from 2010 on PubMed about BG meters which ends its conclusions with:

"Without information regarding recent BG values and the current rate and direction of BG change, as provided by continuous glucose monitoring technology, reductions in the analytical error of single BG determinations may be insufficient to affect changes in clinical outcomes."

So basically, most of the meters won't give us accurate information about the trend of BG because of their error rates, and in any case, it's not likely that greater accuracy would improve clinical outcomes.

So where does that leave the advice to test often?

http://www.ncbi.nlm.nih.gov/pmc/article ... ool=pubmed

So where does that leave the advice to test often?

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The advice to test often shows how the food affects you.

If your Bg is 5.5 before a meal and 7.5 after a meal then you know that meal has raised your Bg by 2 points and then maybe you can cut the portion next time and see if the reading is below two points.

You will never get the body to behave like an engineered piece of machinery ! The best we can and do do is to use the meters to gauge how are bodies are controlling the Diabetes with our help.

......Got to be better than sheer guesswork and infrequent Hba1c levels that do not give us the whole picture.

I have read the report and it is not just the conclusions you need to read, the body of the report is interesting in particular this statement :

As stated earlier, SBGM systems were not developed to be substitutes for the precise analytical instruments used to determine BG in hospital laboratories. They were developed to provide immediate BG information to patients with diabetes so that they might make their own treatment decisions. SBGM systems have been used since the late 1970s with varying degrees of success by educated and motivated patients in clinical trials such as the DCCT and in routine self-management.

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So where does that leave the advice to test often ?

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It leaves it exactly where it should be.......a major part of ANY Diabetic's attempts to gain good control and better health. It is OUR advice which comes from OUR experience as Diabetics'.....a total of 18 yrs !

By using one meter, as Sue stated you will see the effect of various foods on your Bg levels, surely THAT is the reason we test and why any sensible person would always advocate testing until at least good control is obtained. If a meter reads lower than another by only using one you will see how much it raises your Bg levels, how many points. That is all you need to know.....we already know they are only as a guide. As stated they are NOT Clinical Precision instruments.

Then again.......what do we know........ if you want to lose sleep and get stressed worrying about something which frankly is not a worry.......your choice. Me, I concentrate on looking after MY Diabetes and helping others with advice to help THEM control THEIR Diabetes.......which WILL continue to include the advice to test, test test. :|

We know it makes sense whatever anybody else thinks.

Thanks guys for the advice. Once again it seems that it can be a touchy subject. Apologies. You are one source of useful advice and I hope the site is open to other sources too, such as PubMed which is available to everyone and these trials papers are useful data that might help us all.

For me, the Rx meter is too inaccurate to be trustworthy. Sure a before meal and after meal test is useful but if the error on the meter is greater than the change recorded, it doesn't actually tell us what we expect or need. I appreciate that you want to offer level-headed and consistent advice - I'm not questioning that.

I'll keep looking for better data about these meters and their use. If I find anything useful, I'll post it if that's OK.

It's not a problem but we look at the bigger picture and both have our priorites.

We try hard to convince people that they should test so we just don't want the wrong message to get out.

It's not just us that are discussing this, we are being watched by sometimes 30 -40 'lurkers who heed the advice here and then are puzzled when somebody comes along basically questioning why the need to test. We have to respond to that. Now if people don't want to test, for whatever reason, that is a matter for them.......their choice. We stick to our guns....so to speak. What we do.

Regarding the Pubmed site, again not a problem. There are certain sites not allowed, again for various reasons. Mainly if it is a reputable site and considered useful then we nor Admin have a problem with that.

One thought I had was this business of contacting some manufacturers regarding the accuracy of the meters. Now TBH I just don't have any free time to do this but if you have it would be interesting to see the manufacturers take on the matter. My last contact with any was back in 2009 so there may well be some changes afoot. If you are up for some research I would be interested to know what they are up to at the moment and if they are planning any better accuracy in newer meters.

No hard feelings.......it's just we look at things from a different perspective.

No probs C. I have been on a low carb for a few months and I've seen quite dramatic changes in BG measured on a OneTouch. Assuming the OT is consistent and the trials do show a good record of accuracy, then my change is a real one. At the same time, the Rx meter was all over the place. If I judged the trend from those readings, I'd just be completely confused by the apparent random jumps and drops.

Just now I tested two minutes apart on the left little finger at 6.5 and 6.7 on the OT and 7.5 and 8.9 on the Rx. That means the Rx could really be indicating anything from 6 to 10.7 - I could reasonably pick any number in between with equal justification, which for me is hopeless. Maybe it's just a duff meter although it says it's OK with the test solution.

I completely agree with the idea of regular testing - it's the only thing we have to enable us to control the choice of diet. I certainly don't think anyone should stop testing. But it does bug me that these meters can have such an enormous variation even within the EU guidelines. It's even the case that the accuracy of the meters varies within ranges of BG so it might be really accurate at very low BG levels and hopeless at high ones. They get an average accuracy level rating!

If we have a reasonably reliable meter, like the OT seems to be, then the monitoring makes sense and gives us really valuable information. I think we have to test regularly anyway and then make a judgement about the accuracy of the data. Without the data we have nothing. With it, we can at least make an informed choice.

I don't have lots of time but I'll see what I can do in contacting some of the manufacturers - no doubt they'll have some trial data about the accuracy of their meters.

All the best.

I have just got one, and tested twice, it compared to my one touch ultra is 1. above, will need to record more testing, but only got 10 strips, and if no good dont want to invest.

re all the above listings, did anyone argue against testing?

I for one could not live without testing

I was hoping this meter would be good, so we all could buy it and force prices of others down, thus pleasing the powers that be

I've been in touch with the manufacturers of the GlucoRx and they've kindly sent me some trials data which I'm analysing at the moment. The data relates to their conformance with the ISO 15197 standard along with a range of other meters.

That ISO standard for accuracy actually only says that they should be accurate to within ±1.1 mmol/L for values below 5.5 mmol/L and within ±20% for higher values (they state the values in mg/dl). So simply conforming with the ISO standard in place in the EU doesn't actually require a high standard of accuracy. It basically means that if the reading is 7.0 mmol/L, that might be somewhere between 5.6 and 8.4, a pretty wide range. Quite where it really is depends on whether the meter is biased to read higher or lower, and also the scatter pattern of the errors. That data is very hard to find but the Rx guys have sent me some.

The important point though is that even if the meter meets the EU standard, that doesn't mean it has a good standard of accuracy because the ISO standard is quite low. A number of endocrinologists have argued that these meters need an accuracy of at least ±5% to give diabetics proper control but at present, I don't think there are available portable meters that can match that standard.

The data I've seen so far about the Rx meter shows that around 99% of their test figures fall within the ISO standard range. The OneTouch scored 100% but as I said, it's not a particularly high standard of accuracy to meet.

We have to test, and test regularly, but we also need a realistic view of the accuracy of the devices so we don't kid ourselves that we know more than we really do. I've found the Rx consistently higher than the OneTouch and they can't both be right. My OneTouch agrees very well with the lab tests.

Once I've had a chance to go through the data, and I've asked some other manufacturers without response so far, I'll post something in the way of comparison data. In the meantime, the Rx folks have offered to send me the latest Nexus meter to try out. Perhaps it will prove to be more comparable to the OneTouch.

Just using two meters will not give you any useful results :cry:
try testing with a test solution with a known BG level

The only way is to use three meters and use a voting system to vote out any one of the meters thats set % out of range from test solution .

if you only use two meters how do you know which one is correct ? if any

This is the way we analyze pp02 in CCR rebreather under water real life support equipment

ie three sensors feed PPo2 data to a computer that takes all three readings then computes an average reading of ppo2 . all this is done in real time every second, then opens and closes a valve to replace O2 used by the diver
If one sensor is out of range it is voted out by the other two then a alarm then comes up
the diver would then pass a known % o2 over the cells if reading was the same could carry on
using equipment to the surface , if not would have to bail out to a know safe gas mix for the depth

bowell said:

Just using two meters will not give you any useful results :cry:
try testing with a test solution with a known BG level

The only way is to use three meters and use a voting system to vote out any one of the meters thats set % out of range from test solution .

if you only use two meters how do you know which one is correct ? if any

This is the way we analyze pp02 in CCR rebreather under water real life support equipment

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Yes, I'm aware of the testing methodologies and the only reason I currently accept the OneTouch in preference to the Rx is because it agreed accurately with lab tests in the past. Of course, that might be coincidence given the stated accuracy of only +/-20%. The same would apply to three or more meters. Choosing arbitrarily between one or the other is, as you point out, pointless and I wouldn't do that.

Testing against a known test solution would be OK providing I could accurately produce one of my own but I don't have access to lab equipment. The supplied solutions only indicate an acceptable range of readings for the meters which are fairly wide. They don't give me a specific concentration so I can see a specific error. That's unfortunately the case with some of the published accuracy data as well - it just says x% of the readings were in the +/-20% range, so claiming 100% simply means no better than +/-20% which isn't very good. In any case, whole blood is quite different from a test solution which is why they only suggest a range: the haematocrit value can make a big difference as can a number of other factors.

A voting system wouldn't work in the case where the error range is greater than the spread of readings. It's a pragmatic solution which really only detects malfunction and is fine for checking equipment which has already been certified to a certain standard. In the case of these BG meters, that standard is so low that often the error range is greater than the differences we are interested in.

For example, if we tested with five meters, giving a range of 6.0 to 8.0, it's possible that the top two have a positive bias and should be discounted and so the true value ought to be much lower, perhaps 6.5. Or the reverse could be true, we just don't know without the data. Ruling out the extremes is making an assumption that might not fit the data. I've already seen some data that shows bias even when the spread of error is quite low.

In addition, there are some meters where the errors do not spread much at higher glucose levels, i.e. their accuracy doesn't decline much across the range of readings. Accu-Check meters seem to be good in this respect. Others seem to be much more variable.

It is these problems that motivate me to try and get some data from the manufacturers and try to assess them critically. The Rx guys have so far been very cooperative and are taking the questions seriously.