• Guest - w'd love to know what you think about the forum! Take the 2025 Survey »

hba1c measures over how long?

T

the_anticarb

Well-Known Member
Messages
1,045
Dislikes
Spiders, winter, bills, ignorance, prejudice
Over what period of time does a Hba1c measure? I thought three months but saw the nurse today and she said 6 weeks. My result wasn't as low as I'd have liked but I only changed my diet 7 -8 weeks ago so would be good to know whether my diet before then is affecting the result
 
That's what I thought. Nice to know the specialist nurse knows what she's talking about! :)
 
The quoted average lifespan for a red blood corpuscle is 120 days. That means complete repacement of all corpuscles will happen over that time span. thus to make sure that all are new since last testing, you would need to wait about 120 days, however useful information could probably be deduced over a shorter timespan.
 
The A1c tends to be biased towards the more recent timespan, it's not really an average though. More of a weighted average, and the weighting may vary depending how long your own corpuscles live.

Clear as mud eh? Sorry . . .
 
Ouch, does that mean haemoglobin has a different glucose uptake according to the corpuscle's age? :shock: Oh how I wish things were kept simple for us scientifically-challenged types! :)
 
kegstore said:
Ouch, does that mean haemoglobin has a different glucose uptake according to the corpuscle's age? :shock: Oh how I wish things were kept simple for us scientifically-challenged types! :)
Click to expand...

No, the point is that the longer a cell lives the more glucose it may pick up. I'm trying to remember the term used by someone elsewhere who works with control systems, something like a "leaky accumulator".

As the oldest cells die they were most likely to be glycated. The new cells haven't had time to be affected yet. So any condition which turns your red cells over faster or slower than average can bias the A1c.

Imagine two lumps of iron left out in the rain, one for a day and one for a month. The A1c would be an average of the two different amounts of rust.

Now imagine you put out a new lump each day, and then when the oldest one has been there three months you take it away, then keep on removing the oldest piece as you add a new one.

The average amount of rust will have some relationship to the amount of rain in that three months.

More analogies available on payment of a small fee.
 
Back
Top