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Confused re HbA1c and bg meter

G

gillytee31

Well-Known Member
Messages
53
Type of diabetes
Type 2
I have been diagnosed as diabetic for 3 years, been on tablets for 21 months and insulin for 9 months. On August 25th I had an appointment at the diabetes department at my local hospital and my HbA1c was 37 despite my BG meter showing readings between 8 and 10 . I was told that the probable reason was either anaemia, faulty meter or sustained hypos. A blood test showed no anaemia, my meter was changed but still showed the same readings, and I am sure I have not had any hypos. A month later I had my 6 monthly review at the GPs and the HbA1c was still only 39. I was told to halve my insulin by half to 12 in the morning and 3 in the evening. As I was about to go on holiday I did not take this action till I came back (Monday 24th). My Bg was 14.6 at 6.30pm last night just before I took my insulin, and before my evening meal, 18.4 at 10.30pm when I went to bed and 13.2 this morning. Can anyone suggest why there is this huge discrepancy between my HbA1c and BG readings, and what I should do.
 
Some people have a higher turn over of red blood cells than others, this gives the effect of lowering HbA1c, because, at any one time you have more new, fresh, unglycated cells and less glycated (sugar attached) ones. This could be bringing down your reading - falsely. This is not caused by too much insulin, so the solution is not to reduce it. It is a weakness in the HbA1c approach.
If 39 is a genuine result, that's great, perfect. Why lower the insulin if you are not having hypos?
It sounds as though your meter, being a replacement, is as accurate as these things ever are and your readings are now too high and will not contribute to long term health. Meter readings are not subject to the same sort of inaccuracies as HbA1c, their inaccuracies have a different cause.
If your sugar levels are too high, there are, in my view, two options. Either increase drugs (back to where you were) or cut down on sugar/carb consumption. Personally I would cut down on the carbs (though taking care not to hypo and to balance insulin accordingly) and try and avoid much of the balancing act between drugs, food and measuring systems.
This is only my take on your problem (so could be complete nonsense) and should not be regarded as medical advice, which I am not qualified to give, but I hope it gives you some assistance in thinking things through.
Sally
 
gillytee31 said:
I have been diagnosed as diabetic for 3 years, been on tablets for 21 months and insulin for 9 months. On August 25th I had an appointment at the diabetes department at my local hospital and my HbA1c was 37 despite my BG meter showing readings between 8 and 10 . I was told that the probable reason was either anaemia, faulty meter or sustained hypos. A blood test showed no anaemia, my meter was changed but still showed the same readings, and I am sure I have not had any hypos. A month later I had my 6 monthly review at the GPs and the HbA1c was still only 39. I was told to halve my insulin by half to 12 in the morning and 3 in the evening. As I was about to go on holiday I did not take this action till I came back (Monday 24th). My Bg was 14.6 at 6.30pm last night just before I took my insulin, and before my evening meal, 18.4 at 10.30pm when I went to bed and 13.2 this morning. Can anyone suggest why there is this huge discrepancy between my HbA1c and BG readings, and what I should do.
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Gilly - I am not on any medication, never mind insulin, so this is really just for your information, and to reassurer you it isn't all that uncommon.

My HbA1c is always higher than my finger prick tests would indicate. It's the same when I use a Freestyle Libre, again, the sensor suggests a lower HbA1c than even the 24 hour traces for 2 weeks at a time, when my way of living (eating, drinking, exercise, sleep) is unchanged.

I have read quite a lot of articles on Google on the potential reasons for these discrepancies and a common, and logical (to me anyway) reason for this seems to be how long any individual's haemoglobin cells actually live. The longer they live, the more chance there is for glycation (sugar sticking to the cell surfaces) to take place. Once the cell dies, the body breaks it down, and this is an all very normal process.

This may not be the reason your numbers don't match up, and I haven't had any tests to prove this is what happens to me, but it makes sense to me that that could be the reason. Because I don't take any medication, am well and still have an low HbA1c, I don't find it too much of a concern, but I can understand why it's more meaningful to you.

Hopefully you can get to the bottom of it all. If you do, it would be fab if you'd let us know what it is. Sharing information is all part of how we all learn. :)
 
I agree with the others that HbA1c tests can be higher or lower than other tests indicate. The average life span of haemoglobin cells is said to be between 2 and 3 months. That is an average and the majority of people will be in this group. Some people will have cells with a shorter life span, and some people will have cells with a longer life span, all perfectly natural. Those that fall in the group with shorter living cells will likely have a lower than expected HbA1c. I fall in the other group - my HbA1c results are always higher by quite a lot than other testing methods indicate (very regular and frequent finger pricking and Libre sensors). Whilst this does annoy me there is nothing I can do about it, so have to accept it. I rely on what my finger pricking and Libre sensors tell me rather than my HbA1c.
 
I agree with the others - my HbA1c is always slightly higher than my meter averages over the same periods, and when I've used my Libre those readings are lower than both the HBA1c and my meter. However the patterns I see for both the meter and Libre are quite consistent in what they're telling me.

Robbity
 
Hi, I have come to same conclusion. Hba1c is an indication of 'average' blood glucose and by no means an accurate measure, it is merely an indicative proxy. But like democracy its the best we have under the circumstances . I have thought about having a fructosamine test but it would cost me because it would have to done privately. regards D.
 
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