Question 1

Which rule should I use — 1800, 1500, or 2000?

Accepted Answer

The 1800 Rule is most commonly used for rapid-acting insulin analogues (lispro, aspart, glulisine). The 1500 Rule is used for regular/short-acting insulin. The 2000 Rule may be used in children or insulin-sensitive adults. All are starting estimates requiring individualisation.

Question 2

Should I give a correction dose if the patient ate recently?

Accepted Answer

If the patient ate within the last 2 hours, a correction may be given on top of the meal dose. Beyond 2 hours, a simple correction dose is appropriate. Avoid stacking corrections within 3–4 hours of a prior dose.

Question 3

How do I adjust the correction factor over time?

Accepted Answer

If frequent corrections are needed, the total daily insulin may need adjustment. The correction factor should be re-evaluated if TDI changes by >10%. Persistently large corrections suggest the basal or prandial regimen needs optimisation.

Question 4

Can the correction factor be used in insulin pumps?

Accepted Answer

Yes. Pumps have pre-programmed correction factors that automate bolus calculations. The same principles apply: the pump adds the correction to the meal bolus based on the current glucose and target.