“You’re gonna be so bored by this CGM download” I chirped to my endo. “Things are so dialed in right now you can barely tell I have diabetes!”
This was the tone as I was wrapping up my most recent endo appointment. Finally, in month nine of my pregnancy, I’m feeling pretty solid on my basal rates, carb ratios, and correction factors. I rarely go outside the lines of my CGM these days, and have been waking up to fastings below 100mg/dL. My endo and I reviewed my CGM download, and she sent me off smiling to the laboratory for an A1c, which I was sure would come back in the fives.
In fact, I had predicted an A1c of 5.7%. How can I be that exact on my guess? Well, I’ve gotten pretty good at using my CGM download as an A1c predictor. If I do a 90 day download of my CGM and look at the average BG, I can use an online A1c calculator to see where I stand. I’ve been doing this for the past two years or so, and it’s never steered me wrong (give or take a .1 or .2% deviation). Literally, for two years running, I’ve predicted my A1c – usually on the nose. I like doing this because it prevents me from being blindsided by an unexpected number. My most recent 90 day download showed an average BG of 119mg/dL which should have yielded an A1c of 5.7%.
Given that this strategy has yet to produce an incorrect prediction, one can imagine my surprise the next morning when I opened an email containing my lab results and saw…6.3%. What. The. Heck?! That wasn’t just a little off..that’s over half a percentage point. Normally, I’d be stoked about that kind of number, but as I’ve blogged before my goal during this pregnancy has been to keep my A1c under 6%, per the instructions of my doctors and my own goal of lowering my risk as much as possible.
I was pissed. And confused. And convinced that those labs simply had to be wrong. The lab report itself contained its own estimated average blood sugar, which for an A1c of 6.3% is 134mg/dL. Right there, things were not adding up. My CGM is taking 288 readings every single day – nothing can provide a more accurate average than that thing. And if my download showed 119%, where on earth was this coming from? I emailed my doctor and let her know that although I’m not one to argue with the numbers, I just felt like this one made no sense, and I gave her my reasoning. She wrote back shortly suggesting we get it drawn again, and add in testing my fructosamine. I’d never heard of or taken that test, but she noted it can be a good way to verify A1c.
I went back to the lab the next day (good thing I’m at the doctor 100 times a week anyways) and got it pulled again. The next morning: 6.2%. Still making no sense! The fructosamine was a little more revealing, although I had to do some serious Googling, consulting with my personal physician assistant (that would be Jacob), and a bit of math, but essentially, the fructosamine looks back a few weeks – not months – like A1c does. That test also showed that I should have an A1c in the fives, at least for the last month or so. That gave me some peace of mind and proved that at least for the last month, I haven’t been imagining how good things have been.
At the end of the day, I’m not sure what happened. There were about 2 weeks in June where I had some major challenges controlling my BGs – lots of travel and some vacation time with food/exercise challenges. But overall, the numbers simply aren’t correlating. And more than just being upset that my A1 is up, what bothers me the most is knowing just how damn hard I’ve been working, and still seeing a number go up. Truly I have never been more dedicated to my diabetes management than right now. It’s a slap in the face to see that number and I’m still baffled by the result.
Have any of you ever had an A1c (or another lab test) that simply didn’t add up? Did you argue the point, or let it ride? And I’m curious if anyone has ever had their fructosamine measured concomitantly to verify the A1c. This was a new test for me. Let me know what your experiences have been!