Insulin Dosage Calculations

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When your doctor prescribes insulin to treat your diabetes, you need to understand how to calculate your dosage requirements to properly manage the carbohydrates in your diet, your natural blood sugar fluctuations and a pump, if necessary. Mistakes in insulin dosage calculations can have dangerous medical side effects, so it is important to work with your doctor and establish a solid dosage plan for your insulin therapy.

Daily Dosage

If you are a newly diagnosed diabetic and obtaining a pump, you need to identify the total daily insulin dose as a starting point to measure your basal dose. A general guideline from which to start one-quarter of your weight. For example, if you weigh 280 pounds, your entire daily dose of insulin will be close to 70 units between your long-acting insulin and your mealtime rapid-acting dose. This provides a starting point to calculate a basal rate for an insulin pump.

Insulin Pump Dosage Calculation

Log your insulin doses over the course of a week. Track every insulin dose, both fast-acting and long-acting. For example, if you take 20 units of long-acting insulin twice daily, and then an average of 4 units per meal, you take 52 units of insulin daily. Divide that total in half. Your basal insulin, or the amount of insulin your pump distributes throughout the day, is 26 units. The remaining 26 units are dosed in even bolus amounts, or additional doses before each meal, based on how many carbohydrates you eat.

Carbohydrate Insulin Dose

Cover your carbohydrate intake by calculating the insulin dose that your body needs to manage the carbohydrates you are eating. Start with the insulin-to-carbohydrate ratio recommended by your doctor or diabetic educator. Determine how many grams of carbohydrates you are eating by reading the nutrition label. Divide the total number of carbohydrates by the number of units of insulin your body requires per carbohydrate gram. For example, if you require 1 unit of insulin per 15 g of carbohydrates, or 1-to-15, a meal with 60 g of carbohydrates requires 4 units of insulin.

High Blood Sugar Correction

Calculate your high blood sugar correction factor by using the "Rule of 1800." Divide 1800 by your total daily insulin requirement. For example, if you take 40 units of insulin per day, 1 unit of insulin will reduce your blood sugar by 45 points. When you want to adjust your current blood sugar level, determine how many points you need to reduce your glucose reading. For example, if your blood glucose is 200 and your target is 110, you need to reduce it by 90 points. Inject 2 units of insulin to reduce your blood glucose. This ratio may vary by insulin sensitivity fluctuations. Consult your doctor before you change your insulin dose.