Same food, same time of day, different post- glucose levels, WTF!

[TMR254]

For two successive nights I had exactly the same thing for dinner (liver, fried cabbage in butter, natural yoghurt for dessert), at approx the same time in the evening. Two hours later on one night my glucose level was 6,4, and on the next 7,8, when all things were the same. It wasn't even different types of the same food, I literally had half one night and half the other...

Interestingly enough, before breakfast the following day, in each case, my glucose level was the same, 6,8. No influence from the post-dinner levels.

Why?, I am going crazy here!

Thnx

 

[Lucyr]

Meters aren’t as accurate as you think. Also more than 40 different things affect blood sugars.

 

[TMR254]

Thnx, but in both cases I used a finger prick test, not a CGM, which should be the litmus test, no?

 

[Lucyr]

Thnx, but in both cases I used a finger prick test, not a CGM, which should be the litmus test, no?

Fingerpricks need to be within 15% of the true reading, 95% of the time.

Did you time yourself eating it? Maybe you took a minute longer one day. Did you do exactly the same amount of steps both days? Eat at exactly the same time? Have identical levels of stress? Did you ensure the weather was identical temperatures?

 

[TMR254]

Thnx, point taken. Live and learn...

 

[helli]

Our BG is affected by more than just what we eat.
It is also affected by things like stress, how well we sleep, weather, how much exercise we have done, ...
They say there are at least 42 things which can affect our BG.

If I ate the same thing two days running and had exactly the same results, I would be suspicious of my meter.

 

[silentsquirrel]

You don't say what your pre-meal readings were - were they identical?

Your readings post-meal could be considered roughly the same, if you take the mean it is 7.1, and both 6.4 and 7.8 are within 10% of that, well under the allowable 15%.

Finger-prick meters are remarkable bits of kit, but the readings given to 1 decimal place can mislead people into thinking they are more accurate than they are. Think 6.4ish rather than 6.4 not 6.3 or 6.2.
@everydayupsanddowns has a useful table he might post!

Plus all the stuff above about all the other factors involved!

 

[Docb]

@TMR254 - What you eat might be a big one, but there are lots of other things going on that affect your blood glucose at any time. Added to that is the error associated with the meter reading and the message is, don't try and be too cute in trying to work out what the numbers mean.

The meter is an amazing piece of kit and I think it wonderful that it can give a reading anywhere near your blood glucose. But....

My thought for anybody trying to interpret meter readings is first round the reading to the nearest whole number and then begin to think that something is worth thinking about if two readings you might expect to be the same are different by more than 2 units. So, your readings become 6 and 8, they are only two units apart and so the difference is not significant. There is a reasonable chance that if you immediately repeated your second test on a different finger it would have been a 6 or a 7.

Another thought is that if you can keep your waking readings at 5 or 6, get an overall average less than 8 and eat things that do not give readings into double figures, there is a pretty good chance that your HbA1c will be below the diagnosis level.

Welcome to the wonderful world of interpreting blood glucose numbers.

 

[TMR254]

You don't say what your pre-meal readings were - were they identical?

Your readings post-meal could be considered roughly the same, if you take the mean it is 7.1, and both 6.4 and 7.8 are within 10% of that, well under the allowable 15%.

Finger-prick meters are remarkable bits of kit, but the readings given to 1 decimal place can mislead people into thinking they are more accurate than they are. Think 6.4ish rather than 6.4 not 6.3 or 6.2.
@everydayupsanddowns has a useful table he might post!

Plus all the stuff above about all the other factors involved!

Good point, and no, I hadn't taken pre- measurements.

 

[grovesy]

I rarely get the same results with same meals.

 

[Leadinglights]

Good point, and no, I hadn't taken pre- measurements.

If you are just checking that your 2 hour post meal reading is below 8-8.5 then a single reading is OK but it you are checking out your meal then a before and after is much more useful when the aim would be no more than 2-3mmol/l increase.
Remembering the 15% variation allowable your readings were pretty much the same.

 

[everydayupsanddowns]

@everydayupsanddowns has a useful table he might post!

Is this the one?

(from the Useful Links thread)

BG meter accuracy
It can be quite disconcerting for members new to self monitoring of blood glucose to get different results from BG readings taken close together, even when carefully following manufacturers guidance (washing hands etc). All meters for sale in the UK should comply with the following ISO standards 95% of the time, which allows a degree of variation (and 5% of results can read anything at all). If in any doubt, or if a reading doesn’t match how you are feeling, you should check again with a fresh strip.

 

[TMR254]

Is this the one?

(from the Useful Links thread)

BG meter accuracy
It can be quite disconcerting for members new to self monitoring of blood glucose to get different results from BG readings taken close together, even when carefully following manufacturers guidance (washing hands etc). All meters for sale in the UK should comply with the following ISO standards 95% of the time, which allows a degree of variation (and 5% of results can read anything at all). If in any doubt, or if a reading doesn’t match how you are feeling, you should check again with a fresh strip.

Thanks for the info, that is quite a range!

 

[littlevoice359]

A number of years back, I was curious about variability in the Freestyle Optium test strips I was using at the time (because those are the ones on my prescription), so I requested control solution from Abbott and kept a log of the results for a time. I happened to find those results on my system just now and thought they might be relevant to this discussion.

See attached.

 

[pjgtech]