Self-monitoring of blood sugar | Diabetes Hub

Keeping a close eye on your own blood sugar level is an important part of diabetes care. Learn how to monitor it yourself, as well as when you should do it.

Be Proactive

Self-monitoring of blood sugar


Keeping your blood sugar levels within the target range can help reduce your risk of diabetes-related complications.

Self-monitoring your blood sugar levels can help you better understand how food, physical activity and insulin dose affect the levels, and make the necessary changes to optimise your diabetes control.

Blood sugar level targets are individualised in order to prevent risk of hypoglycaemia (too low levels of blood sugar) or other adverse effects associated with blood sugar control that is too tight.

Your blood sugar range depends on: age, lifestyle and overall health. Remember to discuss with your healthcare team if you need to self-monitor your blood sugar, which tools you should use and how often to use it.

When to check blood sugar levels

  • Before meals
  • Two hours after meals
  • Before bedtime
  • Before and after exercise
  • When feeling unwell
  • Other times as necessary, as discussed with your healthcare professional

Why is blood sugar monitoring important?

  • Gives you a clear idea of your blood sugar level at a given time
  • Informs whether you have hypoglycaemia (blood sugar too low) or hyperglycaemia (blood sugar too high) at a given time
  • Tells you how your lifestyle and medication regimen is affecting your blood sugar levels
  • Helps you and your diabetes healthcare team evaluate and determine the best management strategy for you

How to monitor blood sugar

Blood Glucose Monitor

Blood sugar level can be easily monitored using a Blood Glucose Meter.

Wash your hands with soap and water and dry with tissue. Prick your finger and put a small drop of blood on the meter’s test strip.

Your blood sugar level will appear on the meter within seconds.

A blood glucose meter is usually the least expensive home testing option, but it only reveals your blood sugar level at the time of check.

Flash Glucose Monitor (FGM)

It consists of a sensor and a reader, and depending on the type of sensor, it is placed either at the back of the upper arm, on the abdomen or the upper buttocks.

FGMs can be used up to 14 days. It allows you to view interstitial fluid glucose levels at the time of check and can tell you if your glucose levels are rising, falling or stable.

FGMs can also give you a report on the daily pattern of your glucose levels.  


  • Does not require blood sugar (finger prick) calibration


  • Some do not have alarms
  • Sensor readings are not automatically synced with the reader. You will need to flash the reader over the sensor to record your glucose readings

Continuous Glucose Monitoring (CGM)

It consists of a sensor, a transmitter and a receiver. The sensor typically needs to be replaced every 3 to 7 days.

As it collects glucose readings every few minutes, the CGM is able to give you a more complete picture of your glucose profile compared to a blood glucometer.


  • Triggers alarms if glucose levels are too high or low


  • Some types of CGMS need calibration with blood glucose meter (i.e., will require finger prick)

Glucose level targets

Blood sugar
Before food
2 hours after food
Blood sugar
Too High
Risk of hyperglycaemia
Before food
>7.0 mmol/L
2 hours after food
>10.0 mmol/L
Blood sugar
Before food
4.0 to 7.0 mmol/L
2 hours after food
4.0 to 10.0 mmol/L
Blood sugar
Too Low
Before food
<4.0 mmol/L
2 hours after food
<4.0 mmol/L
Your targets may vary depending on your condition; discuss this with your doctor or care team
Back to Top