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Can You Trust Hba1c Results?

Rustytypin

Well-Known Member
Messages
395
Location
UK
Type of diabetes
Prediabetes
Treatment type
Diet only
I had my yearly HBa1C result today, it came in at 6.2% (44?). I was totally shocked at this as my daily meter testing and MySugr both indicated a result at about 5.2 or 34. 6.2 would indicate an average blood of over 7 mmol, a level I rarely see. I checked my meter this evening (Contour Next) against another meter (Trueresult twist) using the same drop of blood and one read 5.3 and the other 5.4. I have been lo carbing for the last two years, currently on about 40gm carbs a day (+/- 10gm daily), so how the h*ll did I get this HBa1C? I have booked an appointment to see the DSN in two weeks time and will ask for another test as this one seems totally erroneous. I know @Bluetit1802 has had a similar problem, so my question is: Can you trust a HBA1c?
 
How often have you been taking finger prick readings and do you know what happens to your BG between tests?
The hB1AC provides an average at all times in the last 3 months (approximately).
Unless you are testing with something like Libre, I would not have much confidence in the estimate from your finger prick tester as you have little idea what you BG is between tests such as when you are sleeping.
 
Rustytypin said:
Can you trust a HBA1c?
Click to expand...
Most people can, but there are a number of conditions that can make it read high or low. It's based on how much sugar "sticks" to red blood cells which typically last 3 months, so if your blood cells last longer or shorter than this it can distort the result. There are also various genetic factors that can affect the result, as can things like anaemia and a whole lot of other stuff.

https://diatribe.org/whats-normal-a1c-when-it-misleading

I'd believe the blood tests rather than the hba1c. Maybe you could ask for a fructosamine test instead?
 
I have frequently tested during the day and I usually start the day at about 6ish and then slowly reduce during the day to get to the low 5's pre evening meal. After meal my bgs are around the mid 5's. They have been consistand for about a year now, which is why my HBa1c has been such a shock. Just tested my post meal levels and one meter read 5.2 and the other 5.3. My GP tested for things like amemia and all tests came out normal. It will be interesting to see what my DSN says in a few weeks time!
 

No, many of us cannot trust the HbA1c. Please have a read of my recent thread.
https://www.diabetes.co.uk/forum/threads/2-hba1cs-2-labs-1-blood-sample.154627/

My HbA1c came back as 43 when all my other data indicated low 30's. (Libre sensor, A1cNow home test, personal data) See what my GP did and what the results were.
 
I am a blood donor so I make sure that my HbA1c is taken BEFORE I donate blood (using my non-donation arm in case of bruising) as donating blood affects the results.
 
If you get the result you want then of course you can trust them.

If you don’t then obviously they are completely untrustworthy.

A very few people will get incorrect results due to various complications. Of course that will mean all of your tests will be wrong, including the one used to diagnose you in the first place.
 
It's not so much results that I want, more results that make sense given the last years testing and lo carbing. As I said above testing rarely goes into the upper 6's let alone the 7's. 90 day averages of over three tests a day is in the mid 5s. My results are so consistent that I can usually predict a reading at any time of day within a few decimal points of a mmol.
 

Same problem that I have, and have had for around 4 years. I know what my levels are like - I test multiple times a day, wear a Libre sensor part time, and have done home HbA1c tests, and they all tally with each other. Only the HbA1c done by my surgery is out by up to 10 points. I can only assume my red blood cells are very long livers.
 
By all means check again. I've always worked on 'trust but verify'
However the readings of 6ish in the morning may be your clue. Depends how high that liver kick overnight is, as it is obviously playing a part. Low 5s after evening meal then 6s in am could easily give you that level of Hba1c
 
To be honest, @rustypin I have separated the finger prick scores/averages/Libre readings from venous blood tests.

My finger prick averages align with the Libre, when I use it, but my venous A1c is always a chunk higher - consistently.

These days I just accept that my finger prick ranges are x-y, whereas my A1c is between a -b.

It's disappointing I can't quite line them up, but I'm reconciled that if I see finger prick blood scores in my usual range my A1c will be fine.
 
DCUKMod said:
These days I just accept that my finger prick ranges are x-y, whereas my A1c is between a -b.
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Mine are similar to your readings.

My venous hba1c was 5.3% / 34 mmol/mol and done at the pathology shop in June, and my ninety day average of testing with my Abbot meter was 5.5.

Near enough close enough for me.

My pathology shop at the private hospital near where I live.

 
Very informative comments but it's left me with the" what is the point of having the Hb a1c " if it's going to be incorrect. I so understand Rustytypin being upset over it though. I'm due for mine in a weeks time and now not looking forward to it at all. Average finger pricking is rarely in the 5's..
 
Moggely said:
Very informative comments but it's left me with the" what is the point of having the Hb a1c " if it's going to be incorrect.
Click to expand...
The way I look at it the hba1c blood test I have done at the pathology shop is the official result, not the one from a phone app or my Abbot meter readings, as they are just guesstimates based on my averages over ninety days.
 
Finger prick 'averages' may be skewed by the fact that:

the first reading would typically be at the lowest value - before we eat.
the second is not at the highest value but 1 to 1.5 hours afterwards ie we do not normally record the highest values.


HbA1c averages are an inference at best.
 
Rustytypin said:
I was totally shocked at this as my daily meter testing and MySugr both indicated a result at about 5.2 or 34.
Click to expand...

I suppose it's all down to what your BG Is doing between your tests. Only my FS Libre has shown me that my BG will start to rise sometimes as early as 4am, 2 hours before I wake up. In fact it's doing it now, I'm typing this at 06:45 and my BG was 6 at 4 am and is now 9. I haven't eaten for nearly 12 hours. and that was roast vegetables and pork, so low carb.
 
I've just checked my 90 day averages at around the time of last year's HbA1c (41) and the average of 5.8 mmol gives an estimated A1c of around 34!
@DavidGrahamJones ,on the very rare occasions I have been awake enough in the middle of the night to check my BGs the tests come out in the mid 5s, my fasting levels average in the low 6s.
I now have to decide wether to resign myself to acknowledging that I'm not catching all the spikes, or perhaps my red blood cells don't last the same time as most peoples (clutching at straws?)
 
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