NICE - blood glucose self monitoring for type 1 diabetes

Self-monitoring of blood glucose

Adults with type 1 diabetes should be offered a choice of real-time continuous glucose monitoring (rtCGM) or intermittently scanned continuous glucose monitoring (isCGM, commonly referred to as 'flash'), based on their individual preferences, needs, characteristics, and the functionality of the devices available (1)

• advise adults with type 1 diabetes who are using CGM that they will still need to take capillary blood glucose measurements (although they can do this less often). Explain that this is because:
  • they will need to use capillary blood glucose measurements to check the accuracy of their CGM device
  • they will need capillary blood glucose monitoring as a back-up (for example, when their blood glucose levels are changing quickly or if the device stops working). Provide them with enough test strips to take capillary blood glucose measurements as needed
• if a person cannot use or does not want rtCGM or isCGM, offer capillary blood glucose monitoring

Self-monitoring of capillary blood glucose

• advise adults with type 1 diabetes who are using capillary blood glucose monitoring to routinely self-monitor their blood glucose levels, and to measure at least 4 times a day (including before each meal and before bed)

Frequency of self-monitoring of blood glucose

• support adults with type 1 diabetes who are using capillary blood glucose monitoring to measure at least 4 times a day, and up to 10 times a day:
  • if their target for blood glucose control, measured by HbA1c level), is not reached
    • Support adults with type 1 diabetes to aim for a target HbA1c level of 48 mmol/mol (6.5%) or lower, to minimise the risk of long-term vascular complications
    • Agree an individualised HbA1c target with each adult with type 1 diabetes. Take into account factors such as their daily activities, aspirations, likelihood of complications, comorbidities, occupation and history of hypoglycaemia
    • ensure that aiming for an HbA1c target is not accompanied by problematic hypoglycaemia in adults with type 1 diabetes
    • diabetes services should document the proportion of adults with type 1 diabetes who reach an HbA1c level of 53 mmol/mol (7%) or lower
  • if they are having more frequent hypoglycaemic episodes
  • if there is a legal requirement to do so, such as before driving (see the Driver and Vehicle Licensing Agency [DVLA] guide for medical professionals)
  • during periods of illness
  • before, during and after sport
  • when planning pregnancy, during pregnancy and while breastfeeding (see NICE's guideline on diabetes in pregnancy)
  • if they need to know their blood glucose levels more than 4 times a day for other reasons (for example, impaired hypoglycaemia awareness, or they are undertaking high-risk activities)
• enable additional blood glucose measurement (more than 10 times a day) for adults with type 1 diabetes who are using capillary blood glucose monitoring if this is necessary because of:
  • the person's lifestyle (for example, they drive for long periods, they undertake high-risk activities or have a high-risk occupation, or they are travelling) or
  • impaired hypoglycaemia awareness
    
    
• support adults with type 1 diabetes to test at least 4 times a day, and up to 10 times a day if any of the following apply:
  • the desired target for blood glucose control, measured by HbA1c level, is not achieved
  • the frequency of hypoglycaemic episodes increases
  • there is a legal requirement to do so (such as before driving, in line with the Driver and Vehicle Licensing Agency [DVLA] At a glance guide to the current medical standards of fitness to drive)
  • during periods of illness
  • before, during and after sport
  • when planning pregnancy, during pregnancy and while breastfeeding (see the NICE guideline on diabetes in pregnancy)
  • if there is a need to know blood glucose levels more than 4 times a day for other reasons (for example, impaired awareness of hypoglycaemia, high-risk activities)

It may be necessary to self-monitor more than 10 times per day

• because of the person's lifestyle (for example, driving for a long period, undertaking high-risk activity or occupation, travel) or if the person has impaired awareness of hypoglycaemia

Blood glucose targets

• advise adults with type 1 diabetes to aim for:
  • a fasting plasma glucose level of 5-7mmol/litre on waking and
  • a plasma glucose level of 4-7mmol/litre before meals at other times of the day
    
    
• advise adults with type 1 diabetes who choose to test after meals to aim for a plasma glucose level of 5-9 mmol/litre at least 90 minutes after eating - this timing may be different in pregnancy
  
  
• clinicians should agree bedtime target plasma glucose levels with each adult with type 1 diabetes
  • take into account timing of the last meal and its related insulin dose, and ensure target is consistent with the recommended fasting level on waking

Reference:

1. NICE (August 2022). Type 1 diabetes in adults: diagnosis and management