or 1 unit for every 20 to 30 grams for a school-age child, depending on the calculation method used. Infants and toddlers need individualized determinations by the diabetes care team.

Typically, the daily total of all bolus doses equals about 50 percent of an individual's estimated daily insulin needs, but the amount could range from 40 to 55 percent. Bolus doses are usually given before eating but are sometimes delayed after food ingestion for infants, toddlers, and "picky" eaters. People with delayed gastric emptying will often program and deliver meal boluses after a meal rather than before.

What's Involved in Determining an I:C Ratio?

You might find that methods for calculating I:C ratios vary among different doctors and different diabetes management teams, based on their particular experiences. Whatever the method used, it's generally considered to be a starting point only, as individuals may differ in their specific needs. A phrase commonly used about diabetes is YMMV ("your mileage may vary"), meaning that what works for one person may not work for another.

Anyone trained in calculating in-sulin doses—usually an MD, a PA, or an RN/RD/CDE—can help you establish I:C ratios. With a bit of practice (and a comfortable knowledge of basal insulin calculation formulas), you can also learn how to do this yourself.

Not all formulas fit all people; this is definitely a situation where YMMV. Always check with your diabetes management team before making calculations on your own. In addition to knowing your total daily insulin dose (TDD, the sum of basal insulin plus all meal bolus doses for 24 hours), you might also need to take into account factors that are unique to you as an individual: lifestyle, growth and developmental status, weight, age, and the presence of other medical conditions, for example.