HbA1c Testing: A1CNow vs Glucomen A1c vs Lab

borofergie

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I've been promising to do this for a while: two weeks ago I tested my HbA1c using the two home testing kits available in the UK, within an hour of getting my NHS HbA1c blood test at the hospital.

Background
I was diagnosed as T2 in March last year, with a HbA1c of 10.2% (taken after a week of low carbing - so I suspect it was even higher before). WIth a combination of Metformin and low-carbing, I got it down to 5.2% at my June test, and my GP told me that he would take me off Metformin if I managed to do the same again. In fact, when my prescription ran out in late July, I decided to stop taking the Metformin anyway.

I didn't bother taking an NHS HbA1c test until 21st November. I had my hospital blood test, before rushing straight home and performing the two home tests within an hour.

Bayer A1CNow
Time till results: ~6mins
a1cnow-selfcheck-unit.jpg

This is the most complicated of the three tests, but is also the most fun to do. You have to suck up some blood into a little test cartridge, shake it up with some liquid before sticking it in the machine shown above. Once you've done that you have to wait while the clock ticks down from 5 minutes.
Result: HbA1c=6.6% :shock: (approximate 3 month average BG = 8.8 mmol/l)

Glucomen A1c
Time till results: 23 hours
a1c.jpg

This is postal kit. You have to fill in the reply slip and then fill two little circles of blotting paper with blood. It took me several pricks before I managed to fill them, getting blood all over the envelope in the process. I ran down the road to get the last post, and the results were in my email inbox about 23 hours later.
Result: HbA1c=5.6% :eh: (approximate 3 month average BG = 6.8 mmol/l)


NHS Lab Test
Time till results: 2 weeks (my GP is kinda busy).
nurse-wih-needle.jpg

Usual. I'd had three abortive attempts to get this done before, but I'd been scared off by the queues at the phlebotomy unit. Timed it right this time and walked straight in. I only cried a little bit when the needle went in and wore the little bit of cotton wool as a badge of pride for the rest of the day.
Result: HbA1c=5.1% :clap: (approximate 3 month average BG = 5.8 mmol/l)
 

borofergie

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Firstly, it's difficult to draw any conclusions from a single set of three tests.

However, I'm very disappointed at the results of the A1cNow test, in particular. I had a spare kit, so I repeated the A1cNow test a couple of days later and got a similar result (6.4%). There is no way that my average BG reading in the last 3 months is anywhere near 8mmol/l, a number that I almost never see 2 hours after eating.

You'd assume that the NHS Lab test is the most accurate, but I don't know for sure. I'd also be surprised if my average BG was less than 6 mmol/l, but that's probably an artifact of the rough conversion equation.

Conclusion
This makes it difficult to trust the home test kits at all. The difference between an average BG of 8.8mmol/l and 5.8 mmol/l is obviously huge.

I've been doing the A1CNow kits about once a month since diagnosis, and I am kinda surprised at they've always given me scores in the 5.x%. Maybe I ran across a batch of bad kits.

I'll repeat the experiment when I go for my next HbA1c test in March.
 

Sid Bonkers

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I would definitely say that the blood tested in an NHS Path Lab would be accurate barring a mix up of some kind, unlikely but possible, and the home testing kits less so as they almost certainly have an inbuilt +- tolerance as do the home blood glucose testing monitors we all use.

Home kits will only ever give a guide to your A1c otherwise our cash strapped GP's would not send us to the hospital to have a nurse take our blood then a porter take our blood to the Pat Lab where a highly trained technician will run whatever test they do using state of the art technology then a secretary will write up the results and send them to your GP. A time consuming and costly exercise!!!

I think a quick home test would be much cheaper than the above :wink:
 

smidge

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Hi Borofergie!

Thanks for this - very useful! I,d been thinking of getting a home HbA1c test kit, but maybe I'll reconsider.

I generally have mine done at the diabetes clinic using the finger-pricking HbA1c tester and i've always wondered how accurate that was. My last one from that method was 6.0 on 9 September. I then had a 'proper' blood test on 4 November and HbA1c was 5.9. (I was a little disappointed with both of those as it had previously been 5.6 in March). However, back to the point :lol: I concluded that both the NHS methods of testing were probably as accurate as eachother.

Smidge
 

borofergie

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Sid Bonkers said:
I would definitely say that the blood tested in an NHS Path Lab would be accurate barring a mix up of some kind, unlikely but possible, and the home testing kits less so as they almost certainly have an inbuilt +- tolerance as do the home blood glucose testing monitors we all use.

I agree Sid, but all tests have errors, and it is perfectly possible for a lab-test to be contaminated. It happens almost everytime an athlete gets a positive drug test (apparently).

Sid Bonkers said:
Home kits will only ever give a guide to your A1c otherwise our cash strapped GP's would not send us to the hospital to have a nurse take our blood then a porter take our blood to the Pat Lab where a highly trained technician will run whatever test they do using state of the art technology then a secretary will write up the results and send them to your GP. A time consuming and costly exercise!!!

Maybe, but there are different standards of testing even in the NHS. Judging by this forum some people get their results almost instantly while others, like me, need to wait a week. There are obviously different testing protocols and levels of accuracy. Although all that really matters is how you perform against previous tests using the same method.

Sid Bonkers said:
I think a quick home test would be much cheaper than the above :wink:

Yes. But not as much fun. I'm an engineer these are the things that turn me on.
 

AMBrennan

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but that's probably an artifact of the rough conversion equation.
For the record, the equation (average blood sugar ~ hba1c) is technically a prediction (which has much greater variance than the "point estimates" given by the conversion charts.
Compare this to, say, the equation to convert from old units (%) to new units, which is an actual equation.
 

noblehead

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borofergie,

Quite a difference in those readings! :shock:

Obviously the NHS lab test is the most accurate and that is the one that matters most, if anything your little experiment has proved that the home testing A1c kits are grossly inaccurate and a complete waste of money.
 

borofergie

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noblehead said:
Obviously the NHS lab test is the most accurate and that is the one that matters most, if anything your little experiment has proved that the home testing A1c kits are grossly inaccurate and a complete waste of money.

Much as I hate to admit it, I agree Nigel.

I'll probably repeat the experiment next time, but it's difficult to take any useful information from those tests.
 

borofergie

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AMBrennan said:
but that's probably an artifact of the rough conversion equation.
For the record, the equation (average blood sugar ~ hba1c) is technically a prediction (which has much greater variance than the "point estimates" given by the conversion charts.
Compare this to, say, the equation to convert from old units (%) to new units, which is an actual equation.

How can it be a prediction? It's measuring the past not forecasting the future.

It might be technically correct to say that if you keep your BG in a certain range then you can roughly predict your HbA1c, but that works both ways.

It's an empirical relationship but there is an equation behind it...
 

Grazer

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The conversion of average BG to hba1c is accurate- the issue is getting a correct average BG for the period, allowing for how long peaks last etc. This is obviously an estimate, or based on a model with certain assumptions. Nonetheless, looking at your post prandial peaks over a period gives you a pretty good idea of wether or not an Hba1c figure accurately refers to your likely average BG or is miles off, so Borofergie's conclusions will be right. I have doubts over my latest Hba1c lab results which I'll pick up on separately at some time, when I'm not sat down enjoying a good Chateauneuf du Pape
 

noblehead

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borofergie said:
I'll probably repeat the experiment next time, but it's difficult to take any useful information from those tests.


Hope you don't mind me asking borofergie but what would be the point in repeating it.... what is it you are trying to find? :?
 

AMBrennan

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How can it be a prediction?
The conversion between average blood sugar and HbA1c is based on regression analysis. Thus the tool (technically) predicts your average blood sugar (which you haven't measured) based on your HbA1c (which you have measured).
 

borofergie

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AMBrennan said:
How can it be a prediction?
The conversion between average blood sugar and HbA1c is based on regression analysis. Thus the tool (technically) predicts your average blood sugar (which you haven't measured) based on your HbA1c (which you have measured).

Sorry to be a pedant, but the word you are looking for is "estimate". You can't predict something that has happened in the past.
 

Grazer

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borofergie said:
Sorry to be a pedant, but the word you are looking for is "estimate". You can't predict something that has happened in the past.

I've heard of a red ant and a black ant, but wot's a ped ant? Is it similar to a GI ant? (that's either a big ant, or an American soldier ant)
 

RussG

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Hi AMBrennan and Borofergie,

Can you please try to keep this discussion on something relevant to diabetes and not let it descend into sniping. For the record, I'm not really bothered about who started it or who is right. Think of it like that bit in the Simpsons ribwich episode where Krusty says, 'It's not important who got rich offa whom or who was exposed to poisonous what...'

This is just a polite warning to both of you to retrench and not let things get personal.

Thanks,

Russ



[for what it's worth, there's a little voice in my head saying, 'hmm. A statistician and an engineer. But which one is right? There's only one way to find out.......FIIIIIGGGHT!']
 

Unbeliever

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Don't wish to argue with you Mr Moderator but I ,for one, was enjoying the discussion. It was quite informative..

My only complaint is about that Sheep. I am trying not to think of "ants" :lol:
 

borofergie

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RussG said:
[for what it's worth, there's a little voice in my head saying, 'hmm. A statistician and an engineer. But which one is right? There's only one way to find out.......FIIIIIGGGHT!']

Russ,

The answer to this is obviously an engineer.

But anyway, I'm on honeymoon in California now, so I promise to be a good boy until Christmas...

Stephen
 

ladybird64

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Don't promise the impossible Mr Borofergie 8)

Hope you and your good lady have a wonderful honeymoon :D