The Insulin Sensitivity Factor (ISF), also known as the correction factor, is the extent to which one unit of quick-acting insulin will reduce your blood glucose levels.
For instance, an ISF of 1:3 means that one unit of quick-acting insulin will lower blood glucose by 3 mmol/L.
Sometimes, your blood glucose levels may go high despite your best efforts. Knowing what your ISF is will enable you to correct high glucose levels down to your target glucose level safely.
The ISF varies between individuals. It may also vary with different times of the day for the same person. Consult your healthcare care team to determine and utilise your ISF effectively.
To minimise the risk of hypoglycaemia when using quick-acting insulin for corrections, we recommend the following:
1. If high blood glucose coincides with feeling unwell, refer to your Sick Day Management plan for guidance.
2. The safest time to administer additional quick-acting insulin is before meals.
3. If you are still working out what your personal ISF is, avoid giving more than 4 units of quick-acting insulin for correction.
4. Discuss with your healthcare team what your glucose target should be.
5. If you have administered quick-acting insulin in the last three to four hours, avoid giving additional quick-acting insulin as the previous injection is still active in your body. Giving more insulin can lead to stacking of insulin doses and hypoglycaemia.
6. If using a continuous glucose sensor, refrain from additional corrections if the trend arrow indicates falling blood glucose levels. Recheck in one to two hours.
7. Be cautions with correction doses in situations that increase the risk of hypoglycaemia:
- At bedtime (Consult your healthcare team for safe correction methods)
- Post-exercise
- If you have consumed alcohol
