Continuous Glucose Monitoring

Definition/Description

Continuous glucose monitors, also called CGMs, provide a way for people with Diabetes Mellitus to read and monitor their blood glucose (sugar) levels. They are small devices known as sensors which are worn just under the skin and communicate to specialist receivers The receivers can either scan the sensor for a reading (intermittent monitoring) or in real time to mobile phones (via Bluetooth). This provides a more agile way to monitor and record diabetes, check glucose levels without having to prick your fingers and can be used by a person with diabetes and their health care provider to assist self-management, time in range and reduce complications of diabetes.

Generally, people with type 1 diabetes should be offered a CGM through the NHS England's implementation plan to improve use of technology in care. Some people with type 2 diabetes may also be offered a CGM to help manage diabetes. 

NICE Guidance recommends that those with Type 2 diabetes administering multiple daily injections (>= 2 injections per day) insulin should have access to a CGM device if the patient is experiencing recurrent hypoglycaemia, severe hypoglycaemia (3rd party assistance), are unable to self-monitor without the support of a health care professional, or require to test blood glucose levels >= 8 times per day or undergo dialysis or have a learning disability.

If you’re pregnant, live in England or Wales and have type 1 diabetes, you should be offered a CGM.

If you’re pregnant and have type 2 diabetes or gestational diabetes you may be offered CGM if you use insulin and meet other criteria. 

They have problematic severe hypoglycaemia (with or without impaired awareness of hypoglycaemia) or
They have unstable blood glucose levels that are causing concern despite efforts to optimise glycaemic control

should be considered for real-time continuous glucose monitoring (CGM).

If you get a CGM on the NHS, you should also get the other things you need like sensors and replacement parts. Further information on the CGM systems can be found on the Diabetes UK website here

Red Flag Symptoms

For suspected type 1, severe hypoglycaemia or diabetes ketoacidosis (DKA) use clinical judgement on sending to the nearest Emergency Department or calling 999.

Hypoglycaemia

Diabetic Ketoacidosis

Guidelines on Management

Always discuss and agree an individual HbA1c target with adults with diabetes. Encourage them to reach their target and maintain it, unless any resulting adverse effects (including hypoglycaemia), or their efforts to achieve their target impair their quality of life.

The HNYICB Continuous Glucose Monitoring (CGM) Policy in conjunction with the HNY Integrated Care System (ICS) Prescribing Formulary (chapter 6 - Endocrine) indicates the availability in the region for GPs and Health Care professionals to follow. This is based on National commissioning guidance and is consistent with the following NICE Guidance:

NG3 Diabetes in Pregnancy: Management from preconception to the postnatal period (published 25 February 2015)

NG17 Type 1 Diabetes in Adults: diagnosis and management (published 26 August 2015; updated 17 August 2022)

NG18 Diabetes (Type 1 and Type 2) in Children and Young People: diagnosis and management (published 26 August 2015; updated 11 May 2023)

NG 28 Type 2 Diabetes in Adults: management (published 2 December 2015; updated 18 February 2026)

TA943 Hybrid closed loop systems for managing blood glucose levels in type 1 diabetes (published 19 December 2023).

Primary care follows the Prescription Formulary Guidance and can offer

Flash Glucose Monitoring - FreeStyle Libre 2 Plus (15-day sensor)

Real-time Glucose Monitoring - Dexcom One+ (10-day sensor, no separate transmitter required- Bluetooth to mobile phone)

CGM initiation can be arranged in primary care with appropriate training of the health care professionals involved. A referral to the diabetes specialist team is not necessarily required. Educational training can be provided to GP practices or community services by the CGM manufacturers in conjunction with the diabetes specialist team as required for advice on their guidance and appropriate management.

The use of CGM is recommended for the management and blood glucose control of those with Type 1 diabetes, alongside a continuous subcutaneous insulin infusion (CSII), Pump system. The insulin pump and the CGM system can combine to create a hybrid Closed Loop System - NICE guidance website under Technical Appraisal (TA - 943) - Hybrid closed loop systems for managing blood glucose levels in type 1 diabetes (December 2023). This provision is managed through the Diabetes Specialist Care Teams.

Even if CGM or isCGM are enacted, prescriptions for capillary blood glucose measurements and ketone blood measuring sticks, will need to be prescribed.

Referral Criteria/Information

DO NOT REFER

Those with type 2, gestational diabetes or with type 1 and pregnancy managed in Primary Care who are happy and safe to continue with a CGM available on prescription.

If concerns arise please used advice and guidance to contact the Diabetes Team to discuss alternative support elements or if a referral is required.

Do not refer those with palliative or end of life care needs

REFERRAL CRITERIA

Referral to the specialist Diabetes team needs to be considered for those who have further issues or elevated HbA1C despite compliance and tritiated medication.

It is advisable to request advice and guidance (A&G) to discuss if a referral is required.

If a person with type 1 diabetes requests a close loop system, this is to be managed through the Diabetes Specialists to provide education on both insulin pump and CGM use.

A&G and referrals should be made through the NHS eReferrals Service (ERS) to Diabetes and Endocrinology.