Understanding Blood Glucose Levels (2025)

On my recent A1c test result was:

Haemoglobin A1c level - IFCC standardised 86 mmol/mol [20.0 - 41.0]
Above high reference limit
NICE GUIDANCE FOR TYPE 2 DIABETES (2002)
Target HbA1c of 48-59 mmoL/moL should be set for individual.

just a bit confused with #a1c normal range of [20.0 - 41.0]? When I always thought it should be much lower.

Am I missing something (above and below)

Past 2 days using the SD Codefree - on waking my blood glucose of 12.2 yesterday and 13.7 mmol today.

I am not sure if the #sd Codefree is accurate. Wonder what others think?

My BG levels after desmond course beginning of 2018 was just 5.7 mmol At this level my target was 4.7.

Thanks for any enlightenment 🙂

The ranges for the HbA1c test are:
30(?) to 41 are "normal"
42 to 47 is called pre diabetic
48 and above gets you a diagnoses of diabetes (even if it goes below this you're still down as diabetic)

To confuse matters, there is another, old scale, that a lot of people use. This one gives small numbers, which look like finger prick results (they're not the same though). On this 48 = 6.5

Jodee said:

My BG levels after desmond course beginning of 2018 was just 5.7 mmol At this level my target was 4.7.

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Was this HbA1c, or finger prick?

Jodee said:

Past 2 days using the SD Carefree - on waking my blood glucose of 12.2 yesterday and 13.7 mmol today.

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Finger prick test, completely different thing to HbA1c.

13.7 at 8.55 before breakfast
21.6 at 11.54 - 2+ hours after food and before lunch

I really am not sure about this.

The first before breakfast I never set the before food symbol
The second reading I set after food symbol

Not sure if I am doing something wrong

I only ate
low sugar cornflakes 20g carbs
teaspoon yoghurt 2g and 4 grapes 1g
Slice of low carb bread toasted with butter 9g carbs
cup of tea
Milk total tea and cornflakes approx 2 gr carbs

Total 34 g for breakfast 😱

water

Ralph-YK said:

Was this HbA1c, or finger prick?

Finger prick test, completely different thing to HbA1c.

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Hi Ralph thanks for answering, the 86 mmol above was the HbA1c test done at docs surgery via seringe and sent to hospital for testing.

the ones done with the SD codefree BG monitor as the finger prick. Monitor set to mmol

Its been put up before a couple of times but I like this image:

Your Hba1c of 88 corresponds to an average blood glucose of 13 and a bit which is in the same ball park as your waking readings, so your meter seems OK. Looks like your BG control has gone "wonk" since your DESMOND course and its time to get back to the professionals to see if they can find out why. A step change in Hba1c happened to me at the end of last year.

Ralph-YK said:

The ranges for the HbA1c test are:
30(?) to 41 are "normal"
42 to 47 is called pre diabetic
48 and above gets you a diagnoses of diabetes (even if it goes below this you're still down as diabetic)

To confuse matters, there is another, old scale, that a lot of people use. This one gives small numbers, which look like finger prick results (they're not the same though). On this 48 = 6.5

Click to expand...

It is very confusing Ralph with 2 different readings for mmol

so the HbA1C at 86mmol can't equate to the sd Codefree reading.

Docb said:

Its been put up before a couple of times but I like this image:

Your Hba1c of 88 corresponds to an average blood glucose of 13 and a bit which is in the same ball park as your waking readings, so your meter seems OK. Looks like your BG control has gone "wonk" since your DESMOND course and its time to get back to the professionals to see if they can find out why. A step change in Hba1c happened to me at the end of last year.

Click to expand...

Many thanks for posting Docb - I've been on 500mg metformin daily for 13 days now and have reduced quantity of carbs but it doesn't look like anything is changing, infact it looks like getting worse.

Jodee said:

just a bit confused with #a1c normal range of [20.0 - 41.0]?

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It doesn't say "normal" anywhere. I don't know what the [20.0 - 41.0] is about, but the rest looks clear enough: your HbA1c is 86 (which is about 13.4 mmol/l) (which is consistent with your readings), and your target for HbA1c should be 48-59 (where in the range is for you and your healthcare team to decide).

Jodee said:

Many thanks for posting Docb - I've been on 500mg metformin daily for 13 days now and have reduced quantity of carbs but it doesn't look like anything is changing, infact it looks like getting worse.

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As I say, time to see the pros and find out what they have to say!

I don’t know what brand of cornflakes they are but low sugar doesn’t mean low carb. Sadly most breakfast cereals are quite high carb. I suggest you ditch the cornflakes as your BG after 2 hours shows you cannot handle them .

I know those blood tests can be confusing initially
I hope this helps
The measurements are actually quite different
The Hb1ac ( mmol/mol) is measuring the glucose that has stuck to your red blood cells over the past 12 or so weeks .

The finger prick we do ourselves (mmol/L) is an on the spot test of our BG levels at that time.

Bruce Stephens said:

It doesn't say "normal" anywhere. I don't know what the [20.0 - 41.0] is about, but the rest looks clear enough: your HbA1c is 86 (which is about 13.4 mmol/l) (which is consistent with your readings), and your target for HbA1c should be 48-59 (where in the range is for you and your healthcare team to decide).

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Thanks Bruce there is no indicator on the blood results page that the figures in square bracket is the normal range but I recall from my hospital bone density scan it was indicated thus so I just assumed it would be the same for all square bracketed figures on hospital test results.

Ljc said:

I don’t know what brand of cornflakes they are but low sugar doesn’t mean low carb. Sadly most breakfast cereals are quite high carb. I suggest you ditch the cornflakes as your BG after 2 hours shows you cannot handle them .

I know those blood tests can be confusing initially
I hope this helps
The measurements are actually quite different
The Hb1ac ( mmol/mol) is measuring the glucose that has stuck to your red blood cells over the past 12 or so weeks .

The finger prick we do ourselves (mmol/L) is an on the spot test of our BG levels at that time.

Click to expand...

Many thanks Lin
The cornflakes gives the carb per grams per serving that's how I know and I usually eat less than the portion size.

that explains a lot about the measurements thanks lin 🙂

Docb said:

As I say, time to see the pros and find out what they have to say!

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Thanks again Doc b, I go for the NHS blood gas monitor instruction on 6 June with diabetic nurse, I sure do hope its comes down by then I really don't want to increase the metformin dose if I can help it.

Guess lunch will be just avocado, lettuce and a boiled egg for lunch, sure hope that is filling enough for me.
I could add a slice of ham to that I guess or not.

I am actually wondering whether to just do the before and after evening meal tests until I see the nurse and if I go wonky before then will contact surgery. I am not getting any symptoms at present.

Jodee - Hopefully not confusing things further, but the units for your HbA1c of 86 are "mmol/mol" versus the units for your finger-prick of 13.7 which are "mmol/L". So "millimoles per mole" versus "millimoles per litre".

They're different animals, and to compare them, you need something like the pic Docb posted.

Hi Eddy

🙄 yes, I need sugar to get my head round this he he - just kidding

praps a very strong coffee 😛

Jodee said:

Hi Eddy

🙄 yes, I need sugar to get my head round this he he - just kidding

praps a very strong coffee 😛

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Hey also, just be aware that cornflakes can be just about the worst thing for anybody, BG-wise, diabetic or not. Everybody's different, but in recent studies a significant number of non-diabetics showed diabetic-level readings after eating them.

It's not just the amount of carbs - that would be too easy! - it's also where the carbs come from. And it's different for everybody, so you really need to test before & after eating to work out what does what to you.

Jodee said:

Thanks Bruce there is no indicator on the blood results page that the figures in square bracket is the normal range but I recall from my hospital bone density scan it was indicated thus so I just assumed it would be the same for all square bracketed figures on hospital test results.

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Actually I think I was wrong and that is the normal range. Just not for people with diabetes.

Eddy Edson said:

Hey also, just be aware that cornflakes can be just about the worst thing for anybody, BG-wise, diabetic or not. Everybody's different, but in recent studies a significant number of non-diabetics showed diabetic-level readings after eating them.

It's not just the amount of carbs - that would be too easy! - it's also where the carbs come from. And it's different for everybody, so you really need to test before & after eating to work out what does what to you.

Click to expand...

Thanks Eddy, need to get a food diary record BG before and after meals.

Eddy Edson said:

Jodee - Hopefully not confusing things further, but the units for your HbA1c of 86 are "mmol/mol" versus the units for your finger-prick of 13.7 which are "mmol/L". So "millimoles per mole" versus "millimoles per litre".

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I never remember the mmol things.
I go on saying HbA1c (scale with larger numbers or small numbers) and finger prick test. The HbA1c is an average that covers 8 - 12 weeks. What you've eaten that day won't have a noticeable effect.
The finger prick test is your BG level at that moment, goes up and down through out the day, and from day to day (as you'll have noticed).

Stredded wheat, no sugar, would make more difference to my BG level than a jacket potatoe. Or a cooked breakfast. It's not just the sugar in breakfasts that makes a difference I'm afraid. Try some instead eggs.