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HbA1c and average blood glucose

O

Okulu

Well-Known Member
Messages
78
Type of diabetes
Type 1
Hi all,
I'm new to this forum, but just wondered if I might be able to pick your brains about something...
I'm type 1 (for 18 years), and started using a pump in July this year. I've just had my first HbA1c done since changing to a pump and it's 7.6%. I was just wondering how reliable this actually is?
The 90-day average on my BG meter is 7.8, 60-day is 7.6, and 30-day is 7.4, and I test on average 15 times a day (sometimes quite a lot more), so do you not think an HbA1c of 7.6% seems a little high as it corresponds to an average BG of 9.5 (according to DUK website)..?
I know everyone must say this, but I really think something seems a little wrong...?
Would be really grateful to know what people think...
Thanks in advance!
 
I would assume that the analysis of your blood for an a1c test is a tried and tested, fairly automated process with little opportunity for human error to creep in.

I further assume therefore that lab test results are pretty accurate and as it shows broad correlation with your own meter why would you doubt it?
 
I'm type 2, unmedicated, but I test upwards of 10 times a day most days, and my averages are always lower than my HbA1c would suggest. If you have a Google round for info on people who are high or low glycators, you will see that a substantial number of people have an HbA1c that does not reflect their meter readings. More and more people are seeing this since the advent of continuous blood glucose monitoring. If you are a high glycator, your HbA1c will be higher than expected. Please don't ask me for the science behind it, it is way above my head, but there is stuff on the internet about it. I would find them for you, but it's Christmas Eve and I'm shutting down now!
 
You may be having spikes just after meals. You may be a "high glycator."
Yes, it seems high. But don't give up yet.
 
Okulu said:
Hi all,
I'm new to this forum, but just wondered if I might be able to pick your brains about something...
I'm type 1 (for 18 years), and started using a pump in July this year. I've just had my first HbA1c done since changing to a pump and it's 7.6%. I was just wondering how reliable this actually is?
The 90-day average on my BG meter is 7.8, 60-day is 7.6, and 30-day is 7.4, and I test on average 15 times a day (sometimes quite a lot more), so do you not think an HbA1c of 7.6% seems a little high as it corresponds to an average BG of 9.5 (according to DUK website)..?
I know everyone must say this, but I really think something seems a little wrong...?
Would be really grateful to know what people think...
Thanks in advance!
Click to expand...



I have been on a pump since August and my pump shows that my average is 8.7, 8.6, 8.5 over the last 30, 14, 7, I was at the hospital clinic yesterday and also had an A1c of 7.6% so I was also a little disappointed, I also know that my average was lower in the previous 30 days. I feel that I do quite a lot of testing after meals, but I know I have spikes that are too high, so that is my next work in progress. Hopefully next time will have been able to make a bigger difference - for me it is still a good change from the 8.4% I have been prior to pumping.It's still early days. Do you have many lows? I think if you do a lot of testing when you are low this can make a difference to averages. e.g I have a 1.4 but after i washed my hands and retested it went up to 5.something.
 
urbanracer said:
I would assume that the analysis of your blood for an a1c test is a tried and tested, fairly automated process with little opportunity for human error to creep in.

I further assume therefore that lab test results are pretty accurate and as it shows broad correlation with your own meter why would you doubt it?
Click to expand...

Thanks for your thoughts, but that's my point - my HbA1c does not correlate with my meter averages. An HbA1c of 7.6% equates to an average BG of 9.5 (here's the converter I used: http://www.diabetes.co.uk/hba1c-to-blood-sugar-level-converter.html)....
 
fairylights said:
I have been on a pump since August and my pump shows that my average is 8.7, 8.6, 8.5 over the last 30, 14, 7, I was at the hospital clinic yesterday and also had an A1c of 7.6% so I was also a little disappointed, I also know that my average was lower in the previous 30 days. I feel that I do quite a lot of testing after meals, but I know I have spikes that are too high, so that is my next work in progress. Hopefully next time will have been able to make a bigger difference - for me it is still a good change from the 8.4% I have been prior to pumping.It's still early days. Do you have many lows? I think if you do a lot of testing when you are low this can make a difference to averages. e.g I have a 1.4 but after i washed my hands and retested it went up to 5.something.
Click to expand...


That's really funny - my HbA1c before starting my pump was 8.4% too! But strange that your current HbA1c is 7.6% despite having slightly higher average BGs to mine... I'm starting to think I'm a 'high glycator' (never herd of it before) but can't find out much about it...
I test a lot after meals too - but I'm always less than 12, often less than 8... What do you call 'too high'?
I do have lows - the amount varies quite a lot, but yep, I guess you're right about that lowering my average...
 
Bluetit1802 said:
I'm type 2, unmedicated, but I test upwards of 10 times a day most days, and my averages are always lower than my HbA1c would suggest. If you have a Google round for info on people who are high or low glycators, you will see that a substantial number of people have an HbA1c that does not reflect their meter readings. More and more people are seeing this since the advent of continuous blood glucose monitoring. If you are a high glycator, your HbA1c will be higher than expected. Please don't ask me for the science behind it, it is way above my head, but there is stuff on the internet about it. I would find them for you, but it's Christmas Eve and I'm shutting down now!
Click to expand...

Thanks for this. Never heard of it before, but I really think this might explain it. What I'm wondering is how it affects me overall - does it higher my risk of complications..? (Sorry, I know you said not to ask you about it, but if not, was semi-hoping someone else might be able to help...?)
 
Okulu said:
That's really funny - my HbA1c before starting my pump was 8.4% too! But strange that your current HbA1c is 7.6% despite having slightly higher average BGs to mine... I'm starting to think I'm a 'high glycator' (never herd of it before) but can't find out much about it...
I test a lot after meals too - but I'm always less than 12, often less than 8... What do you call 'too high'?
I do have lows - the amount varies quite a lot, but yep, I guess you're right about that lowering my average...
Click to expand...

I don't usually eat many carbs at breakfast or lunch so can be less than 10 after 2 hours, often after dinner where I can eat 60/70g carbs I can be in high teens after 2 hours, a couple of times my cannula has detached and then I have been in the 20's for ages, it seems to take ages for me to go back to normal. Today I have been in teens all day, don't know why except maybe a cold coming on, have no ketones and have just tested at 6.8 after doing a temp 110% basal for last 4 hours. I'm going to wait until after New Year and have a good look at what I'm eating and what effect it has!
 
Okulu said:
Thanks for your thoughts, but that's my point - my HbA1c does not correlate with my meter averages. An HbA1c of 7.6% equates to an average BG of 9.5 (here's the converter I used: http://www.diabetes.co.uk/hba1c-to-blood-sugar-level-converter.html)....
Click to expand...

In principle I think there is correlation. Home test equipment has a +/- 20% error with a true blood glucose level higher than 4mmol

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

So in principle I would trust the hospital lab results in preference to the home test results and would therefore suggest that your home bg meter is consistently reading low but well within the permitted +/- 20% tolerance range.

With a true blood glucose level of 9.6 your meter could return a value of +/- 1.92mmol and still be within spec.
 
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@urbanracer, @Okulu, the rules are about to change and most meters are now +/- 15%.

The reality is that only a continuous monitor could possibly give you a real approximation of hba1c. What do your overnight readings look like? They are the biggest driver of hba1c levels and most people don't look at them frequently.
 
tim2000s said:
@urbanracer, @Okulu, the rules are about to change and most meters are now +/- 15%.

The reality is that only a continuous monitor could possibly give you a real approximation of hba1c. What do your overnight readings look like? They are the biggest driver of hba1c levels and most people don't look at them frequently.
Click to expand...

I was aware that the standards are changing and I read (somewhere) that some manufacturers already comply with the new standards. But it is common practice to give manufacturers of medical equipment a year or more after the introduction date to meet new standards before it becomes mandatory. This also gives 3rd party suppliers the opportunity to continue selling whatever they hold in stock and reduce the value of written off stock. So although the new standard will come into effect in May 2016 it would be wrong to automatically assume that every meter supplied after that date complies with that revision.

Also, because the NHS bulk buys to reduce costs, there is no way of knowing if the meter you've been given is really new or it has been sitting on a shelf for several months. My GlucomenLX carries no regulatory compliance information apart from the CE Mark.
 
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fairylights said:
I don't usually eat many carbs at breakfast or lunch so can be less than 10 after 2 hours, often after dinner where I can eat 60/70g carbs I can be in high teens after 2 hours, a couple of times my cannula has detached and then I have been in the 20's for ages, it seems to take ages for me to go back to normal. Today I have been in teens all day, don't know why except maybe a cold coming on, have no ketones and have just tested at 6.8 after doing a temp 110% basal for last 4 hours. I'm going to wait until after New Year and have a good look at what I'm eating and what effect it has!
Click to expand...

Don't worry - it took me ages to sort out how different types of carbs affect me at different times of day - and then just when you think it's all sorted, it all changes again! My IC ratio in the evening if 6g:1u, so you may end up being quite similar if you have found you go high in the evenings too (my DSN said that was far too low a ratio, but it's clearly I need it, so I just ignored that comment!)... Anyway, you'll work it out I'm sure!
 
tim2000s said:
@urbanracer, @Okulu, the rules are about to change and most meters are now +/- 15%.

The reality is that only a continuous monitor could possibly give you a real approximation of hba1c. What do your overnight readings look like? They are the biggest driver of hba1c levels and most people don't look at them frequently.
Click to expand...


Thanks for the advice. I've got another meter so will compare BGs results with that over the next few days and see what emerges...

Overnights are fine for me at the moment - I seem to be about 5-6 all night (but I only test if I wake up - not going to get into this setting alarms over night to test business!).

I think the relatively high HbA1c might actually be because I have iron-deficient anaemia at the moment, which can falselyinflate HbA1c. I think I might also be a 'high glycator', but who knows! Do you know much about this?
 
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