It is widely appreciated that, whilst HbA1c reflects average glycaemia over the last 90 days, it is heavily weighted by glucose levels in the preceding 2-4 weeks before the test is performed. Can anyone recommend a paper that clearly models this?
many thanks
Tim
Dear Dr. McDonald,
That's a very interesting question.
In fact, such questions are equally beneficial to both... the one who asks and the one who tries to answer.. because one needs to put some effort to browse the internet for this. Thank you.
After a search, I could find these refernces and I hope this answers your question..
" the fact that HbAlc required 4 mo to reach a new steady-state level suggests that GHb level reflects the plasma glucose level in the preceding 4 mo. Furthermore, the 50 and 75% changes in HbAlc level that took place 1 and 2 mo after decrements
in plasma glucose suggest that ~50% of GHb level is determined by the plasma
glucose level during the preceding 1-mo period, and that —25% of GHb level is
determined by the plasma glucose level during a prior 1-mo period. The remaining
25% of the GHb level is, therefore, determined by the plasma glucose level during a 2-mo period before these 2 mo. The GHb level does not simply reflect the mean plasma glucose level in the preceding 2- 3 mo but does reflect the weighted mean plasma glucose level in the preceding 4 mo."
The above point is neatly explained in the first reference attached.
[ I attach both the website links and the pdf herewith ].
http://care.diabetesjournals.org/content/16/9/1313.full.pdf
http://care.diabetesjournals.org/content/25/2/275.full
Dear Dr. McDonald,
That's a very interesting question.
In fact, such questions are equally beneficial to both... the one who asks and the one who tries to answer.. because one needs to put some effort to browse the internet for this. Thank you.
After a search, I could find these refernces and I hope this answers your question..
" the fact that HbAlc required 4 mo to reach a new steady-state level suggests that GHb level reflects the plasma glucose level in the preceding 4 mo. Furthermore, the 50 and 75% changes in HbAlc level that took place 1 and 2 mo after decrements
in plasma glucose suggest that ~50% of GHb level is determined by the plasma
glucose level during the preceding 1-mo period, and that —25% of GHb level is
determined by the plasma glucose level during a prior 1-mo period. The remaining
25% of the GHb level is, therefore, determined by the plasma glucose level during a 2-mo period before these 2 mo. The GHb level does not simply reflect the mean plasma glucose level in the preceding 2- 3 mo but does reflect the weighted mean plasma glucose level in the preceding 4 mo."
The above point is neatly explained in the first reference attached.
[ I attach both the website links and the pdf herewith ].
http://care.diabetesjournals.org/content/16/9/1313.full.pdf
http://care.diabetesjournals.org/content/25/2/275.full
I think S. Charles Bronson has explained very thoroughly this topic. For a brief review of the HbA1c assay i would recommend this reference:
http://professional.diabetes.org/Content/Editorial.pdf
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Metabolic Diseases
- Glucose Metabolism Disorders
- Diabetes