Care at NUH

Flash Glucose Monitoring

What is Flash Glucose Monitoring (FGM)?

FGM is a method for measuring glucose levels using a sensor placed under the skin. It records glucose levels in the interstitial fluid every 15 minutes, allowing you to check your glucose without the need for finger-pricking.  

How to make the most of Flash Glucose Monitoring (FGM)?

For those new to FGM, here are some strategies to effectively utilise this technology: 

1. Regular scanning 

Regularly scanning your glucose levels, at least once every eight hours, helps identify patterns and informs necessary adjustments for optimal glucose control. 

Suggested timings for scanning: 

Drop of blood

  • Upon waking  
  • Before and two hours after meals 
  • Before and after exercise 
  • Every two to three hours when stressed or unwell 


FGM readings may differ from finger-prick tests, especially when glucose levels are rapidly changing. If FGM readings do not align with your symptoms, perform a finger-prick test for confirmation. 

2. Understanding blood glucose targets 

Discuss and establish glucose targets with your healthcare team. The aim is to maintain glucose levels within these targets as consistently as possible.  


An example of glucose targets:

Before a meal2 hours after a meal
4-7 mmol/LLess then 10 mmol/L


Modify food intake, physical activity or diabetes medications in response to glucose levels outside your target range. Consult your healthcare team for guidance. 

3. Interpreting trend arrows 

Trend arrows on the FGM display provide insights into the direction of your glucose level changes. 

ArrowsWhat it means
Up arrowGlucose is rising quickly
Down arrowGlucose is falling quickly
Right arrowGlucose is stable

Keep a Diary

Keep a record of your diet, exercise, diabetes medications, and any unusual conditions like illness or hypoglycaemia symptoms. This diary can be maintained using the glucose sensor app, sensor reader or a manual  log sheet. Sharing these records with your healthcare team enhances the effectiveness of your diabetes management. 
Understanding your Flash Glucose Monitoring report
  1. Time in Range (TIR)

TIR indicates the percentage of time your glucose levels remain within your target range. Work with your healthcare team to set a TIR goal as a measurable objective.   

For a target glucose range of 4-10mmol/L, the aim might be to spend over 70% of time within this range and less then 5% below 4 mmol/L. 

RangeGlucose LevelTarget
Time Above RangeAbove 10 mmol/LLess than 25%
Time In Range4 - 10 mmol/LAbove 70%
Time Below RangeBelow 4 mmol/LLess than 5%


Work towards improving Time In Range incrementally, for example, by 5% at a time. 

  1. Daily Patterns

    The daily pattern graph provides insights into how your glucose levels fluctuate during the day. Identify times when you are more likely to experience low or high glucose levels, as well as periods when levels are within the target range. 

    Daily Graph

Reflect on: 

  • Successful strategies (“What went well?”) 
  • Areas for improvement (“What can I do differently?”) 
  • Queries for your healthcare team (“What questions do I have?")
How to increase your time in range?


My Healthy plate


  • Incorporate movement into your day, especially after prolonged sitting. 
  • Aim for at least 30 minutes of exercise, such as brisk walking or jogging, five times a week 
  • Consider a walk before or after meals, particularly those with the highest glucose peaks 


  • Keep medications in a visible location 
  • Set reminders for timely medication intake 
  • Consult your healthcare team regarding adjustments in medication type or dosage 

Images credit: Abbott, Health Promotion Board, Vectorstock

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