I understand the basic concept that it is a (averaged??) snapshot of prior 90 days of blood glucose levels… but what is the value (% or ppm, etc.) and how is it reached?
With a diabetic, glucose levels aren’t always stable. Let’s say you ranged from 150-350 on a given day…what value is given to that “day” in the 90 day picture?
In: 40
There are a few correct answers here, so I will add a bit of nuance.
A1c can be inaccurately low in cases of high red cell turnover, such as sickle cell anemia or bleeding conditions. Average RBC lifespan in a healthy adult is 90 days. If a condition causes RBCs to be lost or recycled more quickly, then there is less time for hemoglobin to be glycated before it gets lost. This will reduce the amount of glycated hemoglobin, I.E. lower the A1C. This is part of the reason why there are multiple clinical definitions of type 2 diabetes, including those that use fasting blood sugar or random blood sugar which are independent of A1C.
This exception doesn’t apply to the vast majority of people but it’s sort of a nifty insight I think.
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