Different results within seconds

[BeadieJay]

I just tested my bsl, having not eaten for about 3 hours, and it showed as 7.0 (126) which I was really surprised at. So I decided to check again, using another finger (on the same hand), and it came up as 5.9 (106), which was much more what I expected it to be.

My control solution is way out of date, so I can't use that to check the strips (but will be phoning tomorrow for some new solution). But what do I do in the meantime? I'm using a new box of strips, started using them last night. How can I trust them at all now? Should I just not bother testing, or keep testing till I get a number I think I should have at any given time? Or should I use another box of strips? :stupid:

[Harold]

It could be just an errant strip, or you may have vial of unreliable strips. I would keep on testing and if the readings don't seem right retest. Go ahead and get the solution and do check. Then if it shows out of the test range or if you get more that are not consistant call the manufacture. They will probably replace the strips. They will ask how old the meter is and the batteries.

[BeadieJay]

thanks Harold - I'll do as you say. It's the first time it's happened to me, so it was a bit of a shock (especially as my new year's resolution (or revolution as my 8 year old calls it LOL) is to check regularly every single day). :)

[Belinda]

Sue what I discovered is that if anything is on your fingers....apple juice or even lotion (warm vanilla sugar here) will change your reading....I am not one that takes out the alcohol prep pads etc...I just pick a finger and stick....or my forearm..

[rzrbks]

Belinda

Sue what I discovered is that if anything is on your fingers....apple juice or even lotion (warm vanilla sugar here) will change your reading....I am not one that takes out the alcohol prep pads etc...I just pick a finger and stick....or my forearm..


Yes, indeedy. Checked one day and reading was over 300/16.6 :eek:. Then I remembered I might have some Sweet And Low on fingers, washed hands and B/G was 98/5.4.

Also, it is normal to get different readings from different places at the same time.

[lgvincent]

How do you know which one is the correct one?

[mark-TN]

On any given test there is a high probability our true BG reading is anywhere from +/- 20% of the meter reading, because of the standards set for meter accuracy. So a meter reading of 126 means that there is a high probability (not 100%) that our actually BSL is somewhere between 126 +/- 25, or 101-151 (5.6-8.4). :eek: Although a majority of readings will hit close to the actual reading, some will stray up to +/- 20% and still even much fewer will stray even more than this. This accuracy (or lack of) is something we have to live with, even with proper technique. This is just a limitation of BG meters that we should be aware of.

If you do a control test and it tests out of range, repeat the test as the same accuracy holds true for a control solution test as well. If it still tests out of range it is either the strips or the meter itself. Meters wear out overtime and if it is older than a year or two I would suspect the meter as well. I recently had a meter go bad on me that was less than a year old (I think this had to do with my high frequency of testing).

Mark

[BeadieJay]

How do you know which one is the correct one?

great question Lowell :thumbsup:

I think Mark answered it with the fact that our meters are likely to be +/- 20% out of the true reading - I've heard this before, and I guess it's impossible to be 100% accurate unless it's tested under lab conditions.

I did wash my hands beforehand though, so the different results weren't because of any food or anything on one finger and not the other. I always wash my hands in hot (soapy) water before testing - anything to help the blood flow more easily!!

Also, it is normal to get different readings from different places at the same time.

I don't understand how this can be. I'll just add it to my long list of things I'll never understand about diabetes :stupid: :whistling

thanks for all the replies :thumbsup:

[dpav]

This is my pet peeve. I hate the plasma meters because they need to have very strick conditions to be close to accurate. Such as do not squeeze the finger, do not take two readings from the same finger, Only use a blood sample that comes out totally on its own and it has to be blood tha comes out withing 3 to 5 seconds. My whole blood meters do not need such tight constraints. I get errors with this as well but they are few. I simply take three tests and the two that match is the one I trust.
These meters can give us a good idea as long as the one we use is consistant. It can be off or on the nose as long as we get used to the settings that it shows us.
I have 5 plasma meters. None of them read the same and none of them give me a reading the same one after the other. I get frustraited because I must be doing something wrong.
So I use the whole blood. I am able to stay under control with that one.
Sorry about rambling
Don

[docta-docta]

Don,
I'm not sure who told you those things.

1) Real, true, honest PLASMA blood glucose readers cost thousands of dollars and are likely to only be found in a real blood lab. If you aren't "spinning down" your blood sample (between 0.5 mL and 1.0 mL) in a centrafuge to separate out red blood cells from the plasma, then you ARE NOT using a plasma blood glucose test.

2) Modern whole-blood testers that you can buy at the pharmacy actually emulate "plasma" testers. How? They go on the assumption that plasma blood glucose values are 20% higher than whole blood. It multiplies the result it obtains from WHOLE blood by 1.20 and the result? A "plasma-calibrated test."

Why? Because people wanted comparable numbers with those that were obtained in the lab tests from their doctor's office.

So in reality, you're testing with a whole-blood tester, but it just skews the result to make it more like a "plasma" result.

Next:

- You CAN squeeze your finger. In fact, it's recommended to do so by many experts. Dr. Bernstein states in his book that he also does this. For a real plasma test, it's important not to break the red blood cells (because they won't spin out in the centrafuge), but since you aren't doing a real plasma test, this isn't any matter.

- As for readings from the same finger, sure you can! Makes no difference. The reason they say you shouldn't is because they don't want your finger "aching" from being lanced.

As for your "whole-blood meters", they are probably over 2 years old and base the result on shining a light through the strip. (This is before the days of electrocoulometric strips, used in meters such as B-D, Freestyle, and One-Touch Ultra). The older meters must be "cleaned" to keep their optics free from dust, to avoid skewing the results when the light shines through to measure light transparency/light absorbency.

There will always be a 20% +/- variance with your meters. You'll also see a 20% difference between your whole- and plasma-calibrated meters. If you want results that are more like the doctor's office, you're safe to stick with the newer plasma-calibrated meters, and don't set your lancet device so high such that your blood gushes out in 3-5 seconds. Makes no difference. The blood doesn't know how long it's been out, unless of course it's clotted. :-)

BTW, Freestyle meters give you a minute to supply the blood, and the AccuCheck Compact gives you about 3 minutes to fill the strip!

[kitty]

This is probably going to sound strange but I find that my middle finger (no plural as I usually only test on my right hand) asways has a slightly higher blood sugar reading than my other fingers :eek:

[docta-docta]

:eek: :whistling

:thumbsup:

[KickStart101]

i ALWAYS CHECK THE BEST OF 3 TESTS, WHEN THEY ARE IRRATIC.
aLWAYS COMES UP WITH THE BEST NUMBER OF 3.

[dpav]

Thanks for the information. Like I said I most likely need to be educated. I did mean the Plasma style meters that you get at the drug store. . I only call the meters the names I have heard my Endo call them. In either case the ones that use the electrical contacts are not as consistant. The ones that use density for reading are more consistant for me so far.

Don

[docta-docta]

Don brings up an interesting point. One problem with the electrocoluolectric strips is that they must not be exposed to high and low temperature extremes, or the glucooxidase enzyme breaks down rather quickly. This being said, one advantage over them is that they take a much smaller sample size (1 uL or smaller). The "electric eye" meters (like Accu-Chek) will be around for a long time to come because everybody has a patent on their own thing.

B-D and Lifescan (one-touch) actually license their strip technology from a third party that owns the patents. Therasense (now Abbott) own some patents on their own strips, but also pay royalties for some of their technology to a third party.

So much money is to be made in the test strip market that it isn't even funny.

You won't be laughing to find out that B-D strips cost approximagely $0.068 USD each to manufacturer. (Yes, I said 6.8 cents). I believe the current retail price for B-D strips is in the neighborhood of 6O to 1OO cents. I imagine the profit margin from other companies is comparable.

[mark-TN]

Don,

2) Modern whole-blood testers that you can buy at the pharmacy actually emulate "plasma" testers. How? They go on the assumption that plasma blood glucose values are 20% higher than whole blood. It multiplies the result it obtains from WHOLE blood by 1.20 and the result? A "plasma-calibrated test."



Thanks that was a very informative post. I believe the plasma reading however is about 12% higher than whole blood. This is the conversion I always used. (whole blood x 1.12 = approx. plasma equivalent) Joslin quotes the difference as 10-12%.

Mark

[dpav]

The bigest thing that matters most is, are our readings consistent. If they are, then we are able to adjust our corrections and keep regulated. This is the main point I have with any meter I use. I own 5 of the electric style, and 4 of the density style meters. My density meters have been consistant in my usage and I have been able to stay regulated with them. So far none of my electric style meters have been consistant, I have had reading beig from 80mg/dsl to 126mg/dsl to the final of 180mg/dsl. All of the reading being done with in 5 to 6 minutes. At 80mg/dsl I would do nothing. At 180mg/dsl I would bolus an amount of 18 units from my pump. How would I know which one to use had been my confusion, and since I have consistancy with one of my meters, That is the one I use. I don't care how they work as long as I get regular readings that do not varry in large degrees. I like the newer types. But so far I have not felt comfortable in trusting them.
Thanks for the help and information. The education helps.
Don

[Clint]

I just tested my bsl, having not eaten for about 3 hours, and it showed as 7.0 (126) which I was really surprised at. So I decided to check again, using another finger (on the same hand), and it came up as 5.9 (106), which was much more what I expected it to be.

My control solution is way out of date, so I can't use that to check the strips (but will be phoning tomorrow for some new solution). But what do I do in the meantime? I'm using a new box of strips, started using them last night. How can I trust them at all now? Should I just not bother testing, or keep testing till I get a number I think I should have at any given time? Or should I use another box of strips? :stupid:

I had this kind of jump when using my forearm and then my finger... but fingers have always been pretty close..

[dws]

Clint A word to the wise...... Never, Never show the nice police officer which finger you used to test your glucose.
don

[rzrbks]

dws
Clint A word to the wise...... Never, Never show the nice police officer which finger you used to test your glucose.
don

"But Officer, you really wanted to know what I was doing and How I did it!!"

[dws]

I've checked the Texas laws and nowhere is there a mention of testing your blood glucose while driving.
BTW, the little old lady was fakeing being disable, she tossed her walker and was behind the light pole in 2 jumps. I'm nowhere near that fast.
don

[decimaldancer]

I just got a morning reading of 297 which after shocked *wtf* I tested again and it was a more normal 146.

Is it the batteries? What is test solution? I certainly didn't get any.

[dpav]

When we get erratic readings the only thing to do is take a series of them and use the average of the ones most close to each other.
The test strips are irregular and not consistent with every meter. They do not have to be so they are not going to be.
This is where I sound bitter.
The main function of testing equipment in industry is making money, not helping us to keep under control.

[Clint]

The main function of testing equipment in industry is making money, not helping us to keep under control.

yup - thats why they GIVE the meters away with a purchase of strips ....