Self-Made Scientists

The daily routine of monitoring diabetes requires a variety of hats.

Scott K. JohnsonBy Scott Johnson

December 2006 — I'm not a highly educated man - high school diploma, a few college classes here and there, and a whole bunch of life's lessons. I've been dealt a hand of living life with type 1 diabetes so I have had to learn a lot about the body's inner workings – both how a non-diabetic metabolism works as well as a diabetic metabolism.


I have had to play the role of a dietitian, trying to understand how the food choices I make impact my blood sugars, and how I feel.

I have filled the shoes of an exercise physiologist, often times not really knowing it, just doing what I need to do in order to survive a session of basketball or a kayaking trip.

I have played psychologist, trying to cope with some challenges that living with diabetes presents; trying to understand the mental blocks that sometime impede my ability to accept conditions and do what is needed.

I have thought like an engineer, troubleshooting problems associated with pumping insulin. Is my high blood sugar a result of a possible blockage in the infusion set or a crimped cannula? Or is my blood sugar high for some other reason?

I am also a self-made scientist, thinking about the different pieces that go into trying to manage blood sugars. There are so many ratios and factors that we use. Here are the essentials:

  • Insulin to Carbohydrate ratio. This figure tells you how many grams of carbohydrates one unit of insulin will (usually) cover.
  • Correction Factor. This figure deals with how many blood sugar points one unit of insulin will (usually) lower.
  • Basal Rate. This is the rate of flow for your "background" insulin. In an ideal scenario, this rate will keep your blood sugar steady when no other variables are involved.
  • Duration of Insulin Action. This is the amount of time any bolus insulin is in your body and actively lowering your blood sugar.

The fact that these figures are sometimes different for different times of day multiplies the number of numbers we have to use.

There are some wonderful tools out there that can help you get started. Working with your health care team, they can get you pretty darn close to where all those numbers need to be for your individual needs. For many people, that will be just fine. For others, there is no other way to get to that "next level of control" other than to run some experiments. You need to put on your scientist hat and get down to business.

In order to either confirm the numbers I've been given, or have figured out, I need to set up and execute a few experiments. Just like what I imagine a scientist would do, I work to eliminate variables, figure a way to track and record my data, and a plan to test and re-test until I'm nearly one hundred percent confident that my results are reliable.

Let's take a look at my duration of insulin action. The objective of this experiment is to see how long my blood sugar continues to drop after a bolus. In order to have some room to operate, I will need to start the experiment with a blood sugar that is higher than my target, something like 180 mg/dl (10.0 mmol/l).

Starting at 180 mg/dl I will take a correction bolus. Starting at about three hours post bolus, I will start testing my blood sugar every half-hour or even every fifteen minutes until it stabilizes and isn't dropping anymore.

That will give me one set of data points. I would want to repeat the experiment at least one more time to see if I get identical results. It would be even more reliable if I could repeat the test and again get identical results. The amount of time that it took my blood sugar to stop dropping and level off is the duration of insulin action for me.

This particular experiment is useful in that I am also able to see if my correction factor is working or not. If it is, I should end up at my target blood sugar when it's all said and done.

Now, let's think for a moment about the amount of time and energy something like this takes. First of all, I want to run this experiment at a time where I'm feeling confident that there are not other variables mixing things up. I want to be sure that what I'm seeing is a direct result of what I'm testing. Running this experiment when I've got the flu, or did some exercise that I don't normally do, would not be a good time. It would add too many unknown variables to the mix. I need to be able to do frequent blood sugar tests after that three-hour mark. I would need to have the time to sit and watch my blood sugar.

It does take a lot of time to run an experiment like this, but it's not only the actual time that makes it a hard experiment to run. What also makes it hard to run is actually finding a time period where there is a limited set of variables playing games with your test results!

This is just one example of the testing involved in really fine-tuning your control. You should be able to appreciate why it can sometimes take a very long time and a lot of experiments to nail things down. It is not something that just falls into place all on it's own.

With that being said, the rewards of doing testing like this is the confidence that those figures you are using in your calculations are accurate and will get the job done. The frustrating part is that it's never set in stone. If you experience any drastic life changes (gaining or losing weight, dramatically altered daily routine, etc.) these figures may change. In most cases though, once you take the time to test this out and confirm your figures, they will serve you for a long time to come.

Some may criticize the thought of me calling myself a self-made scientist. I certainly do not mean any disrespect to any highly trained and educated professionals. But I say that if I've been able to come up with my duration of insulin action, confirm it, and prove it over the test of time – that I'm able to call myself pretty much whatever I want. We'll also have to remember that my duration of insulin action is only one of the many different figures that I rely on for daily management. If any of those single figures are off, it will cause problems and confusion every single day.

I'm a self-made scientist because I have to be.

Visit Scott's blog.


dLife's Viewpoints columnists are not all medical experts, but everyday people living with diabetes and sharing their personal experiences, most often at a set point in time. While their method of diabetes management may work for them, everyone is different. Please consult with your diabetes care team before acting on anything you read here to find out what will work best for you.

Last Modified Date: June 12, 2013

All content on is created and reviewed in compliance with our editorial policy.

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by Brenda Bell
Well maybe not so much a furor as a controversy. The question, bluntly put, is whether or not a single HbA1c reading should be sufficient and adequate to diagnose diabetes — and whether the conditions under which the test was conducted should have any bearing on the diagnostic or non-diagnostic value of the test. The lede from
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