Basal Testing

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I have been basal testing since the end of March, for almost two months now.  Those of you that might be new to Type 1 Diabetes might be wondering what is basal testing.  To generalize a little bit, a non-diabetic person’s pancreas uses insulin to break down sugars in the body.  A T1D’s (person with Type 1 Diabetes) pancreas does not produce insulin and therefore insulin shots or an insulin pump must cover the body’s deficiency.  A T1D who uses an insulin pump (as opposed to getting insulin shots) receives two types of insulin doses. The first type of insulin a T1D receives is bolus insulin.  A bolus is used for two things: to correct a high blood sugar or to cover carbohydrates from meals.  The second is a base amount of insulin received continuously every hour.  This amount is different for each person and can vary depending on age, weight, activity level and other factors.  This hourly rate of insulin is called the basal rate.  The basal rate can vary throughout the day, with many people needing a little less during the day while they’re more active, and more at night while at rest.  The amount of basal insulin one needs also changes throughout their life, younger T1Ds who are going through growth spurts typically need more insulin than older T1Ds, so basal testing is needed throughout a T1Ds life to account for these changes.  Basal testing is testing to see how much insulin is needed on an hourly basis to keep blood sugars steady. If a person’s basal rate is adjusted properly, their blood sugar levels will remain constant during testing. If it’s too high or too low, their blood sugars will drop or rise accordingly. The doctor recommended level for fasting blood sugar is usually around 80-90 mg/dl (please check with your doctor to determine yours).  Hopefully one day I will get to the point where I feel comfortable with my blood sugar in the range, but for now I am hoping to get my fasting blood sugar between 90-130 mg/dl.

To basal test, you have to fast, or not eat or drink anything with carbohydrates, during the hours you are testing.   Basal testing should be done every so often to maintain good control of your diabetes.  I have found basal testing to be very hard and so I have never really done a complete testing where all my rates are tweaked to be perfect.  These past two months I have committed to testing my basal rates.  I knew the basics going into the fasting, but there have been quite a few things I have learned over the last two months.

Basics (things I knew before starting the tests):

  • Try to stick to as normal a routine as possible
  • Stop the test if your blood sugar gets under 70 mg/dl and correct for low
  • Stop the test if your blood sugar is over 250 mg/dl and correct with bolus insulin
  • You should stop the test if your blood sugar rises over 50 mg/dl 2 hours after your last mealtime bolus (although I always rise over 50 mg/dl so I usually ignore this)
  • Basal insulin should be around 40-50% of insulin/day (I find this to be debatable as I’m getting around the 30% mark for my basal insulin
  • Don’t suspend pump or disconnect pump during test (this seems obvious though, right?)
  • Don’t drink alcohol
  • Don’t test if you are sick
  • Dawn phenomenon is when your blood sugar rises in the morning hours, requiring more basal insulin around 2AM-8AM

Tips (things I learned over the past 2 months):

  • Start the test 4 hours after your last bolus
  • Testing every 2 hours is good to see changes
  • Don’t test 2 days before or after your period
  • You need less insulin throughout the day because you are more active but you are also more sensitive to insulin between 10PM-2AM (generalization)
  • Don’t eat high fat foods, as they can delay the effects of carbohydrates
  • To make adjustments, start around 2 hours before you want to see a change
  • Change by 0.1 or 0.05 at a time
  • Water is your best friend
  • They say not to drink caffeine but I drink Diet Coke religiously and I didn’t notice any changes. One recent ADA study found no correlation between caffeine intake and fasting glucose levels:
  • Overnight is the worst because getting up every two hours results in basically no sleep (although they say you only have to check one over night but my overnight rate was really bad so I still woke up every 2 hours to check to see when a change was needed)
  • Though it’s not recommended, a few times I kept going if my blood sugar was over 250 because I knew I would drop a lot
  • If your blood sugar drops/rises by more than 30 mg/dl during the test period then your rates are too high/low so adjust accordingly (some sources said 40 mg/dl)
  • I read somewhere that you shouldn’t test two days in a row, especially since lack of sleep from an overnight fast will throw your body off the following day

I’m sure I’m missing a ton of other great tips/basics so please share any yours!  In my next article, I will talk about my results from all of my days of basal testing.

Basal testing survival tools

Basal testing survival tools


3 thoughts on “Basal Testing

  1. I. Hate. Basal. Rate. Testing. Ugh!

    So much work, and so hard sometimes! But boy, when those basal rates are set right, you can certainly tell.

    I’m way overdue for some testing of my own. I just keep procrastinating.

  2. Pingback: Basal Testing results | Below Seven

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