Care at NUH

Using the Insulin Sensitivity Factor (ISF) to Correct High Blood Glucose (for People with Type 1 Diabetes)


The Insulin Sensitivity Factor (ISF), alsoknown as the correction factor, 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. 

​Insulin Sensitivity Factor (ISF) example

Understanding your ISF is crucial for safely adjusting high blood glucose readings to your target level. ISF varies between individuals and can even fluctuate at different times of the day for the same person. Consult your healthcare care team to determine, monitor and utilise your ISF effectively.  

​Insulin Sensitivity Factor (ISF) example


To minimise the risk of hypoglycaemia when using quick-acting insulin for corrections, consider the following guidelines: 

  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.       Initially, avoid administering more than 4 units of quick-acting insulin for correction until your personal ISF is established. 

4.       Discuss with your healthcare team to set appropriate glucose targets.  

5.       If you have administered quick-acting insulin in the last three to four hours, avoid additional doses to prevent insulin stacking 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 
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