The HbA1c converter FAQ
1) Why did you do this:
I was recently diagnosed with diabetes and after reading the newsgroups about the importance of keeping control of blood sugars, I decided to keep track of my readings and come up with an estimated HbA1c. The main reason was that there is so much research out there mentioning the importance of keeping your HbA1c under 6.5% and most people have to wait to see their doctors in order to get the test done. I am aware that there are a couple of home tests, but they cost around US$30 each so I figured this would keep me sane until the next visit to the doctor.
2) How do I know your estimate is my correct HbA1c?
Well, I am certain that my estimate is not your actual HbA1c number. This is only an estimate and not a very good one at that. Before you start picking it apart, let me do some of the work for you. First, this model does not properly assign weights to the different measurements. For example, if you measure your blood glucose one hour after lunch you will have a high number, but this number might be short-lived. On the other hand, if you measure before going to bed and get a low number and this number lasts during the whole night the model gives each one of them the same importance. I also had trouble defining what span of time the HbA1c test reflects. A lot of the literature out there mentions that HbA1c reflects the last three months of average blood glucose levels, while newer studies show that the number might be as low as four weeks. My solution: I made enough space for 100 days of measurement. If you want to compute only four weeks, then only use 28 days.
3) Have you tested this? What formula are you using?
I have not had a chance since I have only been diagnosed for less than three months. The formula I am using is one that I came up with using the Nathan formula to calculate average blood glucose level from HbA1c that I found in the internet. Since I wanted to calculate HbA1c and I had the information about my blood glucose levels, I just used some high-school algebra to work it back. As you can see, I was wrong when I said that I would never use that stuff in real life. The actual formula is (Average mg/dl + 86) / 33.3
4) You are so lazy, I measure my BG ten times a day, you only do it five times. Can you make it so that I can use all my data?
The more data you have, the better your average will be and therefore the better the model should work in theory. In order to use more data, some colums need to be added. I am using five colums because I try to at least do those five tests if I have the time. I have also done more than five tests in a day after a really high blood glucose number, but did not use that information since it might affect the outcome. Also note that another fault of the model is that some days only have one result, while others might have all five. What can I say, the whole thing is imperfect.
5) This is a horrible waste of binary space in my hard drive. Just looking at it has made my blood sugar go up. If I could, I would take my toothbrush and physically brush the interiors of my computer to clean even the memory of its existance in my system. I could do this much better.
Feel free to take this idea and run with it as long as wathever product or spreadsheet you come up with is made available to the public free of charge. I am in no way a great Microsoft Excel user. I am sure people can make this better so please do so. If you want to do changes to it and want to put your version in an internet server, I can upload it here and give you credit as the creator. You can contact me Here
6) Why are some of my readings highlighted?
I use that to remind me about when I have been bad. There is a way to do a cell format in excel called conditional formatting. I set it to highlight any number above 130. If you have better control, you could change it to a lower number. If you don't, then change it to a higher number. You could also disable the formatting. But I thought it was neat.
