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Judith, I'm going to try that, and log my numbers. Thank you for the sugestion.
That happened to me the other day. One number was a little high, and I thought that was odd, considering I hadn't had anything to eat in over 4 hours, and my two hour bg after eating breakfast was fine. But I had 3 completely different numbers on all 3 fingers. My only guess was that 20 +/- variation. I agree it IS weird, lol.
I am glad you asked.
I have seen similar responses. I notice that if I check other fingers on the hand with the highest reading, I will find other fingers whereby the readings vary from 0 to 10 points from the lower reading on the other hand.
I usually average the two readings and always retest if difference is higher than 15 points.
Also this difference is worst when I am not exercising - sitting working on computer. Usually after walking the numbers move closer together.
The other farce not mentioned elsewhere is that your liver and gut dump in the glucose and not necessisarily metered on to your blood system and the even mixing only occurs when after the heart has pumped the lot around your body a few times mixing it up. No, your readings will not be the same all over your body at same time contrary to the experts.
If you want some fun, munch some glucose tablets and immediately watch your glucose readings one after another on your fingrtstick machine at your finger tip and do not have a miocardial infarction as you watch the glucose hammered onto your blood system and see how long it takes to get stabalized back to "average " readings.
Yikes, never tried that! I think I'll pass LOL
The typical deviation of test stripes is stated in the manual. Typically it is 20% and this means the result from the same drop of blood can deviate by 20% of the actual blood glucose. Actually I do not think that there can be a systematic difference between the hands.
Hahaha gotta love cats!!!
I was raised with cats and my parents still have a norwegian forest cat and a turkish van. The most non functional combination of cat races I could think of (balance vs temperament). Of course a scratch was always a good reason for testing. With cats I learned to hide my used stripes away. They think that these bloody things are some kind of catch to chew on Ugh!
I tested on all my fingers this morning, there was a 10 point difference in each hand. however, there was only 2 to 5 point difference in each finger on my right vs 4 to 9 on my left hand. My right hand ring finger is the most accurate.
How do you know that your right hand ring finger is most accurate? Statistically every test has a deviation of +/- 20%. In statistics your small number of tests can not proof your point. In some experiments people are asked to invent the result of throwing a coin (head VS number: 1 VS 0) 100 times. When the invented sequence is compared with the result of randomized experiments you will see that people tend to leave out unlikely cases. So they will hesitate to invent the sequence 111111111111111111111111111111111 although it is not unlikely. In the randomized experiment you will find these unlikely sequences for sure. What I want to say is that:
a) every test result of a stripe is independent from the previous result. Every single test can be expected to deviate up to 20% from the real number. But the deviation itself is a random act.
b) contributing factors: environmental temperature will influence blood circulation, water balance and the catalythic reaction in the stripe. Residue containing carbs on the surface of the finger can influence the outcome. Also with hands in not perfectly dry condition the residual moisture can influence the result. Even the way you squeeze your finger is important. With much force you will increase the tissue/plasma fluid and by hitting a blood vessel more directly you will have more whole blood. The type of blood will influence the proportion of glucose in the fluid. Here the manufacturers just decided that it is more likely to draw plasma fluid from the fingers. Thus they have calibrated their equipment on plasma fluid. As you can see we have some factors involved.
c) even if you compare your results with lab equipment you will have to face the fact that lab equipment has a deviation too. It is smaller but deviation still occurs. So the lab equipment can say 100mg/dl with a deviation of +/- 5%. This means the real BG can be 105 or 95 mg/dl. This means that the test stripe can result in 80 or 120 mg/dl with the same blood and this would be perfectly accurate according to the nature of the measurement. It also means that two tests in a row with 100 and 102 are possible. But this does not mean that the stripes or fingers are more accurate. It just means that the deviation is just a random inaccuracy we will have to live with.
I think it is pretty sure that the deviation numbers of manufacturers are exaggerated to protect themself from liability issues. Some manufacturers even manage to have more accurate results although their manual states it differently. For market clearance they have to meet FDA and EU standards and they will make sure to take that hurdle without problems. In my opinion it is about time to reduce the deviation even more but this decision is up to FDA and EU. At the end this is also a question of cost increase VS accuracy increase and its benefits.
I just came to one systematic influence I have not thought off: in cold conditions it might be that the hand used more frequently might have a better blood circulation. This would result in glucose numbers more representative for the real blood glucose in the main blood vessels. With cold hands we will often see the following effect: we test, then we shake our hands to increase circulation, then we test again and the result is often more than 20 points off. Well, all it needs is some snow in Arizona, LOL.
Good thinking. The other story not told is the fact that our blood system is like a full duplex ethernet pipe system. One pipe inbound and 1 pipe outbound. All sorts of stuff is stuffed on the pipes outbound like glucose, disolved oxygen, hormones, drugs, minerals etc and the inbound pipe returning the exhaust, carbon dioxide, breakdown products, unused glucose etc. Unlike the orderly system of polling, bandwidth sharing, enforced banwidth allocation - token net; things are just stuffed on our veins and arteries willy nilly in no particular amounts.
After heart has pumped the stuff around the system a number of times and liver and gut run out of things to do, random readings at finger tip tend to be stable and predictable. During the loading phase one can get instantaneous readings at any instant that are low, high and heart stopping and then test a few minutes later they are more normal once the rich packets pass by.
In fact, if one watches the CGMS readings versus the caveman fingerstick machine, one notices the cgms is integrating - averaging the readings over time to give one the "AVERAGE" OR MEAN READINGS OVER A PERIOD OF TIME and not the peak readings.
In addition, as this reader comments, activity and use of glucose at any point in time will in fact be going up and down as the skeletal muscle cells store their own reserves locally so that at any given time their may not be an even draw on the blood supply glucose as cells will all be drawing down glucose at different times and randomly so that readings of fingers on hands will vary accordingly.
I doubt that one can really get a consistent reading all over body except when one has been resting, exercising hard and liver/ digestion activity has run out and the saber tooth tiger is not after your butt for a quick snack.