The insulin correction dose determines how many units of rapid-acting insulin are needed to bring elevated blood glucose down to target.
Formula
Correction Dose = (Current BG − Target BG) / ISF
Calculating ISF (Insulin Sensitivity Factor)
- Rule of 1800 for rapid-acting insulin (mg/dL): ISF = 1800 / Total Daily Dose
- Rule of 100 for rapid-acting insulin (mmol/L): ISF = 100 / Total Daily Dose
Example
Patient on 60 units total daily dose, current BG 280 mg/dL, target 150 mg/dL:
- ISF = 1800 / 60 = 30 mg/dL per unit
- Correction = (280 − 150) / 30 = 4.3 → round to 4 units
Important Notes
- ISF varies by individual — adjust based on response
- Correction doses are typically given before meals (combined with carb-counted dose) or for hyperglycemia between meals
- Avoid stacking: wait 3–4 hours between corrections
- Always individualize targets based on patient (e.g., higher targets in elderly or hypoglycemia-prone patients)