HbA1c vs Mmol Measurement

[Portchesterman]

I am 73 and I have been pre-Diabetic for about 10 years in range of HbA1c of 45-46. I have managed to keep it with that range by gradually keeping off bad things like gallons of Ordinary Coca Cola and stopping other suggary things as I get older. However this year my HbA1c has reached 48 and I have had to go on Diabetic register. After reading extensively on recommendation of the Nurse at my practice, I have managed to lose about a 7kg to 81kg from 88kg through cuttng out sugar altogether and cutting portion size. My HbA1c dropped to 44 mid year but has now returned to 48 a few weeks ago.
The thing that puzzles me is that I have taken my Glucose readings over several months several times a week regularly with two different machines both of which give me exact or very similar readings. I have found 1.5 to 2 hrs after a meal my MMol readings are generally around 6-7 and never ever been above 7 which seems to indicate my insulin response is good and puts me well in normal category as far as I understand the measurements. In the morning after I have been up for half and hour I take a 'Fasting' test and generally in range 5.6-6.4, which is from near normal to part way up the pre-Diabetic scale from the measuements I was given.
However my Hba1c is still stubbornly high at 48 a few weeks ago and 44 a few months ago. Can somebody explain why these two indicators are so differrent, in case of post-prandial I am perfectly normal and on fasting I am pre-Diabetic according to my Mmol readings but my HbA1c still shows diabetic.
Is there someting I am missing, if I had not had a blood test and just taken my home reading I would assume I am fine (ish) but according to the blood tests I am Diabetic???.

 

[Ralph-YK]

In the morning after I have been up for half and hour I take a 'Fasting' test and generally in range 5.6-6.4

Do you know if it stays at that sort of level, other than when you eat?

I have found 1.5 to 2 hrs after a meal my MMol readings are generally around 6-7 and never ever been above 7 which seems to indicate my insulin response is good

Depends how long you stay at that. Though it does seem pretty good to me.
I would say your self test results look quite good.

 

[Robin]

The HbA1c test measures how much glucose has stuck to your red blood cells during the past three months, so it can be affected by things like anaemia. If you are anaemic, your HbA1c tends to show up as higher than it otherwise would. I don’t know if this applies to you.

 

[Portchesterman]

Random reading at other times also are in range 6.0 to 6.8. This is what is confusing me as it although my Hba1c reading shows just diabetic all my home test show me as normal or at worst mildly pre-diabetic. I would have hoped when I had the reading at 44 the next one would have progressed down but its gone up again to 48 a couple of weeks ago although my home readings dont show any real change.

 

[Eddy Edson]

An important thing is that the relationship between BG levels and HbA1c isn't a fixed, mathematical relationship. It varies from person to person. The "diabetic" threshhold of HbA1c = 48 mmol/mol was set because in studies, *on average* this corresponds to an average BG level of 7.8 mmol/l, which is where researchers have decided that diabetes begins.

But people can & do vary a lot from this average: it's quite possible to have an HbA1c of 48 mmol/mol but average BG of 7.0 mmol/l or less, for example.

It's good to keep in mind that the HbA1c is used because it's fast, cheap and usually does an OK job of identifying when somebody should take some action. But it's rough & ready and ideally everybody would have a continuous glucose monitor measuring BG all the time and giving a much more precise picture than you get from an HbA1c test.

The original researchers whose studies led to the HbA1c = 48 mmol/mol etc cut-off levels recognised the problem for people like you who are borderline: a real chance that they might get identified as diabetic when their avg BG levels are below the "real" diabetic threshhold.

But here's how I look at things: from a risk point of view there's just about sod-all difference between an HbA1c of 48 versus 42 or whatever. If your HbA1c is in the 40's you probably want to keep an eye on things and maybe try to get levels down, regardless of the exact number. It's a completely different situation than if your HbA1c is up in the 80's, say, where you really *need* to take some action. Dividing people into "diabetic" and "non-diabetic" because they fall a bit on one side or the other of a magic 48 level doesn't correspond to anything real; it's just bureaucracy.

 

[trophywench]

Well - all meters are allowed to be up to 15% 'out' - so although It's not like miles out, if the 6.8 were really 7.9 most of the time - that makes a difference. Meters only measure our BG in that finger that second.

There are rather a lot more seconds in the day than one - so they mount up and collectively, alter what's stuck to our haemoglobin.

 

[grovesy]

Even though I use a Libre to monitor my blood sugar , its estimate of what my HBA1C is not the same as my actual HBA1C that is tested in the Laboratory, my last one was out by about my last one was about by about 6 points differnt.

 

[Eddy Edson]

Even though I use a Libre to monitor my blood sugar , its estimate of what my HBA1C is not the same as my actual HBA1C that is tested in the Laboratory, my last one was out by about my last one was about by about 6 points differnt.

You can never know what's more accurate. Clinically, obviously the important thing is BG. The only point of an HbA1c is to estimate your average BG levels over the last few weeks, for which purpose it's only rough'n'ready. So if you could be sure of the Libre's accuracy, you'd care about results from that & not the HbA1c result. But Libre's aren't all that accurate, at least in my experience, so ....

Anyway, the moral for me is not to stress abut exact levels.

 

[Nick Cliff]

Hi @Portchesterman as others have said, your numbers look good so you must be doing something right with your diet and exercise regime. As @Eddy Edson has pointed out, the blood tests are an aide to whether and how much you are at risk, and Pre-diabetic and T2 Diabetic are just labels.
I have been labelled T2 for 10 years and not yet requiring medication. My numbers are not as good as yours, and my GP is happy for me to continue with my diet and exercise lifestyle without recourse to medication, though I have low BP and no weight issue which also guided her decision. We're all different. .and the target HbA1c levels are only a guide.
Whatever the label they want to give you, suggest you carry on what you are doing and don't let the D word worry you. Provided of course you feel fit and well.
Best of luck. Nick

 

[Drummer]

My home testing numbers are about the same as yours after eating but my Hba1c is 42. I even reduced from 50 gm of carbs a day to 40 and it still stuck at 42.
As I understand it, the Hba1c test was correlated to blood glucose levels by testing the two and matching what was found, so abnormal rates of red blood cell replacement can give Hba1c levels which do not match up with the blood glucose levels.

 

[everydayupsanddowns]

Welcome to the forum @Portchesterman

An HbA1c of 48 suggests that whatever you are doing to help manage your BG levels is working well, and that you should keep doing it. At that level you are at low risk of developing any long-term complications of elevated blood glucose levels. 🙂

Some people are ’high glycators’ where more of their blood glucose affects red blood cells than average, but as others have said all the measurements carry degrees of imprecision and uncertainty too - so at the end of the day the important thing is to recognise that your blood glucose needs managing, and you seem to be doing that well 🙂

 

[Portchesterman]

Welcome to the forum @Portchesterman

An HbA1c of 48 suggests that whatever you are doing to help manage your BG levels is working well, and that you should keep doing it. At that level you are at low risk of developing any long-term complications of elevated blood glucose levels. 🙂

Some people are ’high glycators’ where more of their blood glucose affects red blood cells than average, but as others have said all the measurements carry degrees of imprecision and uncertainty too - so at the end of the day the important thing is to recognise that your blood glucose needs managing, and you seem to be doing that well 🙂

I am encouraged by feedback which indicates everything is pretty much under control. The annoying thing for me with a mild heart problem and esonophylic asthma, another thing I now have to declare for travel insurance is being Diabetic although frankly probably I dont have a serious problem. At 73 and have a small place in Spain,(when I can get there!!) this just adds to the cost as its another preexisting condition even if as most people have pointed out I may not have a real problem due to the rather arbitary nature of HbA1c measurement.

 

[Annette&Bert]

I have read about the Libretto Freestyle and wondered how good it was before I purchase one.

 

[trophywench]

It ain't a piece of music (a libretto) - just check the website out, to begin with Annette. Then consider what use you could actually make of it, before investing, as it isn't prescribed to T2s usually.