Hba1c

[Mileana]

Hello all,

I was wondering about a1c results.

Basically, how much of this results comes from the last month, and how much from earlier?

Is there an approximate formula/rule of thumb?

I think I read somewhere that so and so many percent was from recently and only a fraction from 'before', and I seem to not be able to get a proper hit on google to enlighten me on this. Maybe someone knows?

 

[Squire Fulwood]

I don't know the answer to that and I wish I did but when I want to read up on something I usually go to the mayoclinic web site and they say this.

Glycated hemoglobin (A1C) test. This blood test indicates your average blood sugar level for the past two to three months. It works by measuring the percentage of blood sugar attached to hemoglobin, the oxygen-carrying protein in red blood cells. The higher your blood sugar levels, the more hemoglobin you'll have with sugar attached. An A1C level of 6.5 percent or higher on two separate tests indicates you have diabetes. A result between 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes. Normal levels are below 5.7 percent.

 

[xyzzy]

Hi Mileana

I think it's supposed to be around 60% with a fair chunk of that from the last 14 days. Grazer told me the breakdown at some point so hopefully he will correct me if I'm wrong.

However ...

Stephen (borofergie) found this stuff a while back which is very interesting

http://www.diabetes.co.uk/diabetes-forum/viewtopic.php?f=15&t=29164&p=272402&hilit=hba1c#p272402

To sum up it says for some biological reasons nigh on all an hBA1c is from the last 4 weeks of which the majority comes from the last 14 days so the "3 month" average thing is rubbish.

Personally not quite sure. My 4.98% hBA1c from yesterday came at a time when my levels have been a bit higher in the last 2 weeks than the few weeks before that.

My previous 5.3% hBa1c was higher than I was predicting at the time I got it. I got that 3 months ago and 3 months prior to that was when I was diagnosed at 11.3% so that implies some of the hBA1c does come from more than a month back.

 

[Anonymous]

My instruction sheet from Bayer says that 50% of the result is from the last 30 days, 25% from 30-60 days and 25% from 60-120 days.. not saying that's right but that's what it says.

 

[librarising]

HbA1c is a weighted average of blood glucose levels during the preceding 120 days, which is the average life span of red blood cells. A large change in mean blood glucose can increase HbA1c levels within 1-2 weeks. Sudden changes in HbA1c may occur because recent changes in blood glucose levels contribute relatively more to the final HbA1c levels than earlier events. For instance, mean blood glucose levels in the 30 days immediately preceding blood sampling contribute 50% to the HbA1c level, whereas glucose levels in the preceding 90-120 day period contribute only 10%.

http://www.clinlabnavigator.com/Test-In ... n-a1c.html

Hope this helps

Geoff

 

[Mileana]

It does, thanks all - just trying to work out my 4 week avg from hb1ac compared to my measured average of tests.