While at my regular 90-day endo appointment yesterday, I had a point of care A1c check performed. This is the first A1c after I started supplementing iron last month. I was curious to see if, as described in the cited study above, my A1c number would match up better with my CGM average glucose values.
My BG averages:
14-day - 93 mg/dL (5.2 mmol/L)
30-day - 94 (5.2)
90-day - 95 (5.3)
This American Diabetes Association web page has a calculator that converts an A1c into an average blood glucose and will also take an average blood glucose and translate it to an A1c.
I put in my 90-day CGM average of 95 mg/dL (5.3) and found that it is equivalent to an A1c of 4.9%. In the last 10 years, my A1c always floated about 0.5% above what the background average blood sugar predicted. What was my A1c yesterday? It came in at 5.0%! Only a 0.1% divergence from my average glucose.
I had a complete blood count (CBC) panel done yesterday as well. My hematocrit and hemoglobin tests both measured just above the lower lab limit, while the red blood cell count measured just below the lab limit. So, in comparison to the CBC drawn six weeks ago, my hematocrit and hemoglobin both improved and moved into range while the red blood cell count did not change and remained below range.
While I will continue to watch this over time, I think this circumstance suggests that low blood iron levels affected accuracy of the A1c to reflect my overall glucose exposure.
I’ve never received an A1c as low as 5.0% before and am blown away by what feels like a breakthrough for me. I know it’s just a number but it’s one that affirms the every day effort I put into controlling my BGs.
Some people have suggested that the A1c serves as an indicator of glycosylation on other tissues in the body. I don’t think this is true to the extent iron deficiency skews the A1c number higher than actual.