Continuous Glucose Monitoring

What is Continuous Glucose Monitoring?

A standard fasting blood glucose or HbA1c test gives you a single reading — a snapshot taken at one point in time. Continuous Glucose Monitoring (CGM) records your glucose level automatically every few minutes, day and night, producing a detailed picture of how your body responds to food, activity, sleep, and stress over an extended period.

A CGM sensor is a small device worn on the skin — typically on the back of the upper arm — for a period of one to two weeks. It measures glucose in the fluid just beneath the skin and transmits readings to a smartphone app or reader device. No finger-prick calibration is required. At the end of the wear period, the full dataset is reviewed by our clinical team at a report consultation.

Who benefits from CGM

• People with type 2 diabetes: Understand how your current medications, meal choices, and activity levels are affecting glucose control between clinic visits. CGM data informs medication adjustments with far greater precision than an HbA1c alone.
• People with prediabetes: Prediabetes often produces significant post-meal glucose spikes that do not show up on a fasting test. CGM reveals this hidden dysregulation and allows targeted dietary and lifestyle changes before the condition progresses.
• Individuals optimising metabolic health: Even with entirely normal fasting glucose, some individuals experience patterns of glucose variability associated with long-term cardiometabolic risk. CGM provides the insight needed to make truly personalised lifestyle adjustments.

What your CGM report shows

• Time in range — the percentage of readings within your target glucose band
• Glucose variability and standard deviation across the wear period
• Post-meal glucose spikes by food type and timing
• Nocturnal glucose patterns and any overnight dips
• Effect of exercise and physical activity on glucose levels
• Stress and sleep-related glucose changes
• Estimated HbA1c calculated from continuous data

How to prepare

• Wear a loose-fitting or sleeveless top so the back of the upper arm is easily accessible on the day of sensor application.
• Ensure the back of the upper arm is clean and dry. Do not apply any moisturiser, lotion, or oil to that area on the day of your appointment.
• Download the relevant companion app for your sensor on your smartphone before your appointment if possible. Our team will confirm which app to use when your appointment is booked.
• Inform the clinic if you take paracetamol regularly in doses above 1 gram, as this can temporarily affect some CGM sensor readings.
• There is no fasting requirement for sensor application.

What to expect: A step by step guide

Step 1: Sensor application at the clinic
The CGM sensor is applied by our clinical team during a brief appointment. It is placed on the back of the upper arm using a small, spring-loaded applicator. The process takes under a minute and causes minimal discomfort. No needle remains under the skin after application.

Step 2: Activation and scanning
The sensor is activated using the companion smartphone app. Depending on the sensor model, glucose readings are either transmitted continuously via Bluetooth or retrieved by holding your phone close to the sensor. Our team will walk you through this at the time of application.

Step 3: The wear period
The sensor is worn continuously for the duration of the monitoring period, typically 10 to 15 days depending on the sensor used. You can shower, swim, and exercise normally. CGM sensors are generally water resistant for showering and brief swimming. Avoid prolonged submersion. If the sensor detaches before the end of the wear period, contact the clinic for guidance.

Step 4: Keep a food and activity log
To get the most from your CGM data, keep a simple written or phone-based log of your meals, meal times, exercise sessions, and any significant events such as illness, stress, or disrupted sleep during the wear period. This log is reviewed alongside your glucose data at the report consultation and helps explain the patterns your data shows.

Step 5: Sensor removal and report review
At the end of the wear period, the sensor is removed by peeling it off gently. In most cases this can be done at home without a clinic visit. Your glucose data is then reviewed by our clinical team and a report consultation is scheduled to go through your results, explain what the patterns mean, and agree on next steps for your care.

Important limitations to be aware of

• CGM measures glucose in interstitial fluid, not directly in the blood. There is a physiological lag of approximately 5 to 10 minutes between interstitial and blood glucose readings.
• Readings may be temporarily less accurate during periods of rapidly changing glucose — such as immediately after eating or during intense exercise.
• Certain medications, including high-dose paracetamol, can affect sensor accuracy with some CGM devices. Inform your physician of all medications you are taking.
• CGM is a monitoring and clinical insight tool. It does not replace laboratory blood glucose or HbA1c testing for diagnosis or formal clinical decision-making.