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calling experts on hbA1c

weeezer

weeezer

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bristol
hi

some of you out there are rather knowledgable on this...i have tried to have a look on this forum but can't seem to find much.

2q's - firstly, my latest hbA1c was apparently '51' which converted to 6.8, why is it '51'? my nurse said it was american? presumably this is new? (what does an hbA1c actually equate to? i.e. what does 6.8 mean in mmol? i know it's not 6.8 like on meter, but thought roughly it meant averages of about 8.8...am i hugely wrong?)

secondly...my mum (t1) was told to have her lastest A1c blood test first thing in the morning so it was fasting, she asked why this was necessary as it had never mattered before, they said it was for more accurate results.

any info/experience of same thing? i do wonder if they are getting confused with fasting glucose tests, as my last one just happened to be fasting because it was for cholesterol as well, this resulted in them testing my glucose level which, when all the results came back, my gp rang me to say was (at 10.7) too high. i thought he was referring to A1c as i had never had a blood glucose via a blood test before, and he just said 'diabetic blood test results'. it worried me no end, only when i happened to talk to a nurse who told me it was 6.8 did i realise what had happened.

any ideas?
 
Hi weeezer,

Your 6.8 result comes out at somewhere slightly below 8 mmol/l (average).

To the best of my knowledge, fasting won't affect a HbA1C result as the variation in what it measures (glycated haemoglobin) is too long-term for short-term fasting to matter.
 
Hello weezer

Have a look at this converter which is on the homepage on the left side. Click on Toolbox and then you will see the drop down menu.

http://www.diabetes.co.uk/hba1c-to-bloo ... erter.html


Regarding your hba1c - as long as its not high enough to put at grave risk for developing complications but more importantly it's not so low that your hypo awareness starts to get somewhat variable, then everything will be ok :)
 
Hiya! The 51 is the new ifcc units as opposed to the % measurements we're used to. I've not checked but 51 sounds like about 6.8% which is about 8.8 mmols - again not checked specifically but sounds about right from memory.The HbA1C is different to your meter in that the meter checks your blood as it is at that moment. A1C looks at the glucose platelets attached in different units of measurement and reflects an average of your blood sugars over the previous few months. There is absolutely no need to fast for the A1c - it does not improve accuracy. Sometimes we're asked to fast because we might be having another test at the same time that DOES require fasting. Often it's just ignorance on their part. I had an argument with my doc and DSN on this. They spoke to an endocrinologist who specialises in diabetes. He confirmed no fasting.
Well done on a good result!
 
weeezer said:
secondly...my mum (t1) was told to have her lastest A1c blood test first thing in the morning so it was fasting, she asked why this was necessary as it had never mattered before, they said it was for more accurate results.
Click to expand...

More than likely they are going to do a cholesterol check at the same time checking her lipid panel, last time I had my review they did both checks the week before so they were ready in clinic the following week.
 
To convert HbA1c to new IFCC

IFCC = (hBA1C -2.15) x 10.929

so new IFCC is hBA1C subtract 2.15 then multiply that result by 10.929.

To correctly do on a calculator because of the brackets in the formula:

enter your HBA1c value
press -
enter 2.15
press =
press x
enter 10.29
press =

what is now showing is your equivalent IFCC

To convert IFCC back to HbA1c

HbA1c = (IFCC + 23.497) / 10.929

so hBA1c is IFCC add 23.497 then divide that result by 10.929

To correctly do on a calculator because of the brackets in the formula:

enter your IFCC value
press +
enter 23.497
press =
press /
enter 10.929
press =

what is now showing is your equivalent hBA1c

Sorry for the maths lesson if you know about brackets!

On your IFCC of 51 you should get the answer 6.81 ish
 
Sorry I am a little confused now[so no change there} My surgery never does fasting tests for diabetics [or so they say}
Whenever I have an HBA1C they also do the full works , cholesterol. lipids. triglicerides etc.

Does this mean that only the HBA1C results are accurate and reliable? That the cholesterol lipids etc need me to have a fasting test?
 
Good question. I'm always told to fast for cholesterol, and most seem to say that, but I have seen posts saying you don't even need to fast for cholesterol. My guess would be that it wouldn't make a big difference but I don't know.
 
Thanks. I can remember someone once asking if the cholesterol tested was just for that monment in time {like a blood glucose meter] or oif that was some sort of "average " like the HBA1C. I am not sure if I ever saw the result of that discussion {intermittent blindness} but will check now.
 
The search facility on this forum can be very sarcastic. Doesn't it know that diabetics can often have difficulties wih their vision? :lol:
 
my doc said cholesterol has to be fasting, i asked what if i'm low the morning of test, he said orange juice would be fine coz no fat in it, only anything that contained fat would affect test, so according to him it mattered. (hmm, i don't have much trust for what they say anymore :cry: )

i've had many a disagreement at my surgery about hbA1c tests, the last few times they've always tried to get me to get it done first thing, insisting it needs to be done fasting.

IFCC? DCCT? you lot are good. i have no clue what these are! must do better...
 
Thanks for that weeezer . I will query it nex time. Not hat I expect much sense. If the HCAs do it they won't know anytthing.
if I ask the Nurse =well she was the one who when i queried my T2 diagnosis_ announce bver definitely - You are a T2 ".
Whe I asked how she knew for sure she told me "It says so on the file"! If I ask the dr at the annual review he will tell me to ask the nurse! :roll:
 
AMBrennan said:
Shouldn't that be DCCT units and IFCC units rather than HbA1c and IFCC?
Click to expand...

Yes it should, both figures measure HbA1c but express it in different units. It's rather like 1 metre is the same as 39 inches, they both represent the same physical length but one way uses metres to express the length and the other way inches.

So...

Where I wrote HbA1c substitute DCCT HbA1c (DCCT HbA1c is the full name of the old style, the one everyone has in their signatures.)

Where I wrote IFCC substitute IFCC HbA1c (IFCC is the full name of the new style values)

A quick rough lookup to and from...

DCCT- HbA1c IFCC-HbA1c
(%) (mmol/mol)
6.0 42
6.5 48
7.0 53
7.5 58
8.0 64
9.0 75
 
She shouldn't blame the Yanks for the new way of reporting HbA1cs As technology has changed scientists have become more able to give accurate results but were still calibrating machines according to the standards of 30 years ago ( DCCT HbA1c, based on the agreed standards used for a long term T1 diabetes trial, Diabetes control and complications trial)
Thirty years later we know a bit more about glycated haemoglobin and how much is really present than we did then . There is now a new international agreement on the calibration of HbA1c analysers (by members of the International Federation of Clinical Chemistry so IFCC) which reflects the new knowledge. .
After they agreed to change the calibration then it became clear that they also had to change the units to avoid confusion . If they had continued to use % with this new, more accurate calibration, HbA1c results would have appeared to be 1.5%-2% lower overnight! (a few years back I remember a person on a forum wondering why his HbA1c was now something like 4.1% which was far too low to be a realistic result. It turned out his country had changed to IFCC calibration. This was before the agreement to change units )

Different countries are adopting the new terms/calibration at different times so for a while some will be using the new system and some the old.

Some of the experts who use these figures all the time have looked for quick methods that can give rough conversion s quickly . These are both by British diabetologists/researchers.

Kilpatrick's Kludge

To change DCCT Hb A1c (ie % HbA1c) to IFCC HbA1c (ie mmol/mol)
minus 2, minus 2.
ie if the old figure was 8% take away 2 that makes it 6 in the tens column, take away 2 again and that gives 4 in the units column. DCCT HBa1c 8%= IFFCC 64 mmol/mol
This works for whole number percentages from 4-13%.
For non whole numbers then there's a more complicated method.
Middle's Manipulation
To change DCCT to IFCC multiply by 11 and subtract 24
so to change DCCT HbA1c 6.5% to the new IFCC
6.8x 11=74.8
71.5-24 = 50.8 rounded up to 51 mmol/mol

You can work this one the other way round
so to change IFCC to DCCT add 24 and divide by 11.
51+24= 77
75/11 = 6.8

http://www.idf.org/sites/default/files/ ... ohn_EN.pdf
 
there is a simpler way to convert hba1c% from the tenths of a percent

hba1c 7% = 53 using the minus 2 rule
and then
hba1c 7.5% = 53 PLUS 5 = 58
7.4% = 53 PLUS 4 = 57 etc
for percentages CONTAINING .6, .7, .8 and .9 you have to add 1
so 7.7% =53 PLUS 7 +1=61
7.8% = 53 PLUS 8 +1 = 62
 
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