Giving Context to a Hba1c Result

I really want to get my hba1c done. I have a referral to pathology sitting in my diabetes file at home, to tide me over until my next endo appointment. But I know it’s still a bit too soon. 

I have a pretty good idea of where I’ll be sitting. Yet my deepest, darkest desires are still chasing sight of a number. A scorecard. That stamp of validation, that will tell me how well or not-so-well I have been doing with my diabetes over the past couple of months.

It’s silly, really.

A hba1c is just a number. It’s only one small element in the scope of managing diabetes. In fact, it’s not even the most accurate measure of how I am managing. Although it’s supposed to be a 3 month ‘average,’ around 50% of that result is drawn from the past four weeks worth of blood sugar levels. If there are big variances in my levels, then the result is likely to be less accurate. I was even told that clinic results can vary by as much as 0.5% from pathology!

With holidays and Easter in the rearview mirror, I definitely felt that it was time to sit down and review my data. So over the weekend, I gathered all of my diabetes devices and uploaded their data to Diasend.

Diasend is a brilliant tool for reviewing my diabetes data at home. It’s a web-based software platform, where I can upload the data from my insulin pump, blood glucose meters and FreeStyle Libre. It generates the data from all these devices into one, easy to read report. So for instance, I can see what my reading was at 12pm, the carbs I ate with lunch, the insulin dose I gave for lunch, and the basal rate I had running at the time.

When I review my data, there are five things I like to look at besides from my hba1c, which give me an indication of how I am doing with my d-management.

Obviously, the first thing I want to know is my average blood sugar level over the past 2-4 weeks. I then use this handy tool to convert my average blood sugar level to an estimated hba1c.

The second thing I think about is how often I am checking my blood sugar. I’ve always been in a pretty good habit of checking my levels before and after meals, and before and after significant activity. I also try to check once during the night, if I don’t sleep over my 1am alarm! Checking my blood sugar more than four times a day means that I’m getting a bigger picture of where my levels are sitting through the day, and that my average blood sugar level is accurate.

The third thing I look at is the Standard Deviation in my blood glucose readings. In other words, how high or how low are my blood sugar levels going? How often are these kinds of swings happening? How big is the variability between these kinds of swings? Before I started using an insulin pump and more actively managing my levels, there were big swings. For several years, I was able to scrape together half decent a1c results, but I always knew that they weren’t accurate because of the large deviation. Ideally, my standard deviation should be less than 3 for the hba1c result to be a reliable one.

My fourth consideration is to any significant events that might have influenced my levels lately. I know that I’ve been travelling and eating a lot over Easter. The increased physical activity has produced a few more lows, while the excess of food has produced a few stubborn highs. There’s usually a good reason for everything, and I simply feel so much better about a disappointing couple of days when it can be explained.

Finally, I try to focus on the progress I’ve made since last time. Whether it’s a lower standard deviation, a problem area I’ve been able to fix, or whether I’m simply feeling more comfortable with my management since last time. I constantly remind myself of these victories, to motivate myself going forward.

A hba1c result is an important number. But there is so much more context that needs to be given due consideration, before we begin popping the champagne bottle, or smashing it to pieces.


  1. For so many years we had almost nothing to measure how we are doing with our blood sugar. I recall when the fasting blood sugar was the entire ball game. Miss it and you got a scolding and more insulin. Hit it and you were told to go home and come back in 3 months.

    The A1C is a good but imprecise measure. Like always I am hoping for the next thing and hoping it will be better.

  2. Hi Frank. I get where you’re coming from. It’s hard since we are so conditioned to having a number to define ourselves – report cards if you will. It’s hard to not punish yourself for “bad” numbers and feel validated by “good” numbers. I have a cgm and at first it was challenging to not be overwhelmed by the numbers. I’ve come to a place now, however, where I’ve found a confortable way to manage and utilize the information and not get too stressed by it. Honestly, I feel like I’m blind those occasional times I have a short break between sensors. I made a metaphor for not using a CGM in my post last year during Diabetes Blog Week –

    Anyway, as always, thanks for sharing your thoughts.

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