How does HBa1c test relate to the prick trst?

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Roger Harris

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Hello all.

My HBa1c test gave a high reading. I’ve been told I need to get it down to 67mmol/mol or less as soon as I can.

Does anyone know that relates to the prick test units?

I’m currently testing at 9.5mmol/l. How does that translate into the units used in the HBa1c test?

I need to get a blood test as soon as it’s down to 67mmol/mol - I don’t want to go for it too early, but not too late either. So knowing how the two sets of units relate would really help.

Many thanks,

Roger.
 
Roger Harris said:
Hello all.

My HBa1c test gave a high reading. I’ve been told I need to get it down to 67mmol/mol or less as soon as I can.

Does anyone know that relates to the prick test units?

I’m currently testing at 9.5mmol/l. How does that translate into the units used in the HBa1c test?

I need to get a blood test as soon as it’s down to 67mmol/mol - I don’t want to go for it too early, but not too late either. So knowing how the two sets of units relate would really help.

Many thanks,

Roger.
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Oh I think I’ve found the conversion chart. Would I be right that 67mmol/mol equates to 10.9mmol/l? If someone could confirm I’d be very grateful.
 
There's a converter here which gives a similar figure.

But obviously HbA1c is a roughly 90 day 24/7 average & you can never really replicate that.
 
Roger Harris said:
Oh I think I’ve found the conversion chart. Would I be right that 67mmol/mol equates to 10.9mmol/l? If someone could confirm I’d be very grateful.
Click to expand...
Kind of, sort of.

You can say that on average, people with an HbA1c of 67 mmol/mol have an average daily BG of 10.9 mmol/l.

But obviously a single fingerprick isn't going to tell you what your average BG is over the day. And the relationship between your average daily BG and HbA1c will not be the same as the "average person's".

So it's all kind of rough and squidgy and mushy. Don't look for exactness!

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There's no direct correlation between the two. At best it only gives you a rough idea of where you might be. As an example my most recent HbA1c came back as 41 but when I averaged the 156 finger prick tests that covered the same period the chart suggested I would be lower.
 
Wow! Thanks for all the quick replies 🙂

I don’t need to average my readings but rather just need to be below 67 on the day. I’m approximately 61 at the moment, from the conversion charts, at 9.9.

While I realise it’s a bit of an approximate value I’m encouraged!
 
Roger Harris said:
I don’t need to average my readings but rather just need to be below 67 on the day.
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That's a bit contradictory. If the hospital is going to use an HbA1c test then that can't be anything other than a 90 day average. However if they're happy to rely on a single finger prick then keeping in single figures will hopefully see you OK.

Might be an idea to confirm 100% with them to avoid potential disappointment.
 
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Yes I may not have explained myself well! The hospital took an HBa1C which showed a three-month average which was too high. But in irder for the procedure to take place they only need my blood to be lower on the actual day - I don’t need to wait an extended period for my average to have decreased. It’s a spot-check on the day.
 
Got it. If you're allowed breakfast on the day maybe best to go completely carb free.
 
Roger Harris said:
Wow! Thanks for all the quick replies 🙂

I don’t need to average my readings but rather just need to be below 67 on the day. I’m approximately 61 at the moment, from the conversion charts, at 9.9.

While I realise it’s a bit of an approximate value I’m encouraged!
Click to expand...
An HbA1c is an average of sorts, so even if you get finger prick readings of 9 every day for a fortnight, there are still 10 weeks of blood cells with higher levels of glucose in your blood stream. It takes 2-3 months for those red blood cells to die and be gone, so that higher glucose is stuck there until those cells are replaced, so even if your serum blood glucose has come down, the HbA1c will remain higher until all those red blood cells are replaced with blood cells which have been exposed to the lower levels. This is why it is important to understand that you are measuring different things with a finger prick compared to an HbA1c. Don't want you to reschedule the procedure for 2-3 weeks thinking that you have fixed it when you are likely still over the threshold of 67. That will take approximately 3 months of readings below 10.9 to change the HbA1c.
If however you want to change it more quickly (which isn't really recommended, you could aim for an average finger prick of 5 and that will have a more significant impact over say a month compared to getting 9s for a month. Averaging in the 5s for a month is going to be similar ish to averaging finger prick readings of 9s over 3 months, particularly as the HbA1c is weighted towards more recent readings.
Not sure if that makes sense but if you don't understand I will try to explain it better. The main problem you have is that the glucose stuck to your red blood cells is stuck and you can't remove it, so you have to wait for those red blood cells to die and be replaced by shiny clean new ones, which will then start to attract the glucose from your blood serum but because you have lowered your levels a bit, less will stick to those new cells. The more you can lower your blood serum the less the new cells will attract and the lower your HbA1c. Still not sure I explained that well 🙄
 
As others have said, having a low finger prick at the time of their taking your blood for an HbA1c test is unlikely to make very much difference. The finger prick is measuring your glucose at that moment. The HbA1c is measuring the glucose stuck to your blood cells which have about a three month life. This measures the average of the glucose in all those cells taken.

They are two completely separate measures. Finger pricks are useful to help you know the impact of food you have just eaten, and as you begin to make appropriate choices about portion size, carbs eaten and exercise, these are likely to start to drop. The improved values will show up in your next HbA1c and these are usually not done without a gap of at least three months between the tests. It is quite common for these to be done every 6 months initially and then later once things settle to annually.
 
The hospital is not being petty when requiring a lower HBA1C. There is a reason - a lower hba1c means a better chanc/faster recovery, It is better for you.
You could play the system and go low/no carb for a few days or weeks prior to the surgery when it means your risks are still high?

Apologies if I have made some assumptions here but if it was me, I would want to understand the target they require and why it is important rather than just trying to get below it as soon as possible.
 
You haven't mentioned what surgery you are hoping to have but the dangers of infection and poor tissue healing are much greater if blood glucose is high.
I am surprised that they don't require your HbA1C to be below 67mmol/mol (which is still far too high) rather than just the level on the day which is pretty meaningless in that context as it can vary due to a large number of factors.
 
i used the click here button above and if its right it will be great news to me .
my morning reading 7.5 and its usually lower than that before and after meal and at bedtime marginally so ill go with 7.5 and that comes out as 46 so if thats true thats fantastic from 108. or will my DN be right and i should be happy to get it down to 60?
It is with medication and not home and dry but it would be a huge turn around if i achieve it.
 
rebrascora said:
An HbA1c is an average of sorts, so even if you get finger prick readings of 9 every day for a fortnight, there are still 10 weeks of blood cells with higher levels of glucose in your blood stream. It takes 2-3 months for those red blood cells to die and be gone, so that higher glucose is stuck there until those cells are replaced, so even if your serum blood glucose has come down, the HbA1c will remain higher until all those red blood cells are replaced with blood cells which have been exposed to the lower levels. This is why it is important to understand that you are measuring different things with a finger prick compared to an HbA1c. Don't want you to reschedule the procedure for 2-3 weeks thinking that you have fixed it when you are likely still over the threshold of 67. That will take approximately 3 months of readings below 10.9 to change the HbA1c.
If however you want to change it more quickly (which isn't really recommended, you could aim for an average finger prick of 5 and that will have a more significant impact over say a month compared to getting 9s for a month. Averaging in the 5s for a month is going to be similar ish to averaging finger prick readings of 9s over 3 months, particularly as the HbA1c is weighted towards more recent readings.
Not sure if that makes sense but if you don't understand I will try to explain it better. The main problem you have is that the glucose stuck to your red blood cells is stuck and you can't remove it, so you have to wait for those red blood cells to die and be replaced by shiny clean new ones, which will then start to attract the glucose from your blood serum but because you have lowered your levels a bit, less will stick to those new cells. The more you can lower your blood serum the less the new cells will attract and the lower your HbA1c. Still not sure I explained that well 🙄
Click to expand...
No, that’s brilliant! Thanks for the excellent explanation.
 
I would also like to add that whilst having this procedure is obviously important to you and has therefore focused your attention on improving your diabetes management, your long term health is equally important and you really need to be looking at these changes as long term lifestyle changes rather than a quick fix to get the procedure done.
Once the damage to blood vessels and nerves in your body is done there is no going back, so good management to prevent that damage is ever so important. It is very easy to ignore diabetes because most people don't have obvious symptoms or perhaps just take whatever medication has been prescribed and expect/assume that will sort the problem, but it won't. These changes that you are making now to improve your HbA1c for the procedure are just as important for your long term wellbeing. Fingers crossed you can form some good habits during this period which you will be able to continue afterwards.
Good luck with getting levels down and hope the procedure goes smoothly.... but please don't side line your diabetes afterwards, it is still just as important to manage it well.
 
rebrascora said:
I would also like to add that whilst having this procedure is obviously important to you and has therefore focused your attention on improving your diabetes management, your long term health is equally important and you really need to be looking at these changes as long term lifestyle changes rather than a quick fix to get the procedure done.
Once the damage to blood vessels and nerves in your body is done there is no going back, so good management to prevent that damage is ever so important. It is very easy to ignore diabetes because most people don't have obvious symptoms or perhaps just take whatever medication has been prescribed and expect/assume that will sort the problem, but it won't. These changes that you are making now to improve your HbA1c for the procedure are just as important for your long term wellbeing. Fingers crossed you can form some good habits during this period which you will be able to continue afterwards.
Good luck with getting levels down and hope the procedure goes smoothly.... but please don't side line your diabetes afterwards, it is still just as important to manage it well.
Click to expand...
Thanks for those kind words of encouragement. It’s been a bit of a wake-up call tbh. For years it was really well under control. Testing 5 to 5.5 in the morning, weight good, exercise good. But in the middle of some difficulties I let it slip. Back on the straight and narrow now!
 
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