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Demystifying Basal Terms

Standard, Alternate, Active and Temp: Demystifying Basal Options for Insulin Pumps

So we’ve talked about the Standard Basal program, the Alternate Basal program, and the Temporary Basal setting – and there’s even an Active Basal program… are you confused yet? Wondering what the difference is between the various basal options and when to use which one? Let’s clear up the confusion:

It’s important to point out first that all of these basal programs and settings refer to basal insulin. Basal insulin is the background insulin that the pump “trickles out” every few minutes to keep blood glucose steady in the absence of food and exercise. It is differentiated from bolus insulin, which is given in a “lump sum” to cover carbs or to correct highs.

So keeping in mind that we are talking about background insulin…

The Standard Basal program — or simply “basal program”, “basal rates”, or “basals” — is the primary set of basal insulin doses that you have programmed into the insulin pump to use on a typical day and which, if you never touched the pump again, would automatically deliver a specified amount of insulin every few minutes. Each basal rate is expressed as a discrete unit-per-hour number, such as 3.5 U/hr, or 0.125 U/hr (as just a few examples), which specifies how much basal insulin will be delivered during a given hour of the day.

An Alternate Basal program is a set of basal rates with different doses of insulin than the Standard Basal program, so that you can conveniently switch over to a profile that matches a specific, other-than-usual, but regularly-occurring situation. For example, the rates may be lower than Standard for the afternoons in which your child has swimming lessons, or for the mornings in which you (if you’re the PWD) take a run before work. Or the rates may be higher for couch-potato Sunday afternoons. Just like with the Standard Basal program, the rates in an Alternate Basal program are also expressed as a discrete unit-per-hour number, such as 1.75U/hr (as just one example). To switch into, and out of, any Alternate Basal programs that you have set up, you need to manually select the desired basal program.

The Active Basal program is the one you are using at the moment, whether it’s the Standard or one of the Alternate programs. The others hang around in the wings, waiting until you need them.

A Temporary Basal rate, or temp basal, also alters the Standard basal rates, however it does so by increasing or decreasing the Active Basal program by a certain amount relative to the current basal rates, rather than switching over to an entirely different set of basal rates. A Temp basal is often expressed as a percentage (such as 150%, or -40%, which the pump will convert into a discrete, unit-per-hour basal rate; for example, increasing a basal rate of 3.0 U/hr by 30% (which your pump may express as 130% of, or +30% of the current rate) will result in a temporary basal rate of 3.9 U/hr.) but some pump models also allow you to set a temp basal according to the insulin rate (in units per hour). Unlike an Alternate Basal program, when the temp basal expires (at the end of the time period you specified when you set it, such as 12 hours, for example) the basal rates will automatically return to the usual, pre-temp-basal rates (as set in the Active Basal program).

The above information was reviewed for content accuracy by clinical staff of the Alberta Children’s Hospital Diabetes Clinic.

This material has been developed from sources that we believe are accurate, however, as the field of medicine (in particular as it applies to diabetes) is rapidly evolving, the information should not be relied upon, as it is designed for informational purposes only. It should not be used in place of medical advice, instruction and/or treatment. If you have specific questions, please consult your doctor or appropriate health care professional.

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