Home blood glucose monitoring (HBGM) equipment has been used for over 30 years and has been simplified enormously for the user during this time. It is an important component in the management of diabetes for the majority of individuals. In the late 1970s, HBGM was demonstrated to improve glycaemic control for patients with type 1 diabetes, with the first blood glucose meters marketed for home use around 1981. 

After the results of the DCCT¹ trial in 1993 and the UKPDS² trial in 1998, self-monitoring became widely adopted as a necessary part of diabetes care. It provides immediate information on a person’s glycaemic level and can be an important guide for adjusting all factors that affect glucose control on a timely basis.³

Diabetes management in primary care

The GP and practice nurse are the primary caregivers to people with diabetes in the community, supported by other members of the multidisciplinary care team. The role of the GP includes the diagnosis of diabetes, advice to patients regarding lifestyle changes, monitoring of blood glucose, agreeing health-related targets, commencing medication with ongoing care and monitoring as appropriate.

In order for HBGM to be effective it must be incorporated into a self-management plan for the patient. It can be a useful tool to help the patient and healthcare professional (HCP) identify areas of glycaemic variability that may require adjustments to food choices, exercise and medication. Timing and frequency of testing are important parts of diabetes education. 

Frequency of HBGM in type 2 diabetes

In 2015 the HSE spent €46.5 million on blood glucose monitoring test strips. Despite the high frequency of testing in patients with type 2 diabetes, there was very little evidence to justify its cost-effectiveness.⁴ Indiscriminate testing by all patients with diabetes is not recommended. The National Clinical Programme for Diabetes⁵ issued guidelines in 2015 on the frequency of testing for patients with type 2 diabetes (see Table 1). 

Consider HBGM in the following additional situations:

• Patients with deteriorating glycaemia who may require treatment titration
•  Patients with intercurrent illness
•  Patients on steroids.

Frequency of HBGM in type 1 diabetes

NICE guidelines 2016⁷ advise self-monitoring of blood glucose for all adults with type 1 diabetes, at least four times a day, before meals and before bed. Testing up to seven times a day may be advised in the following circumstances: 

• If the desired target for blood glucose control (HbA1c level) is not achieved
• If the frequency of hypoglycaemic episodes increases
• Before driving
• During periods of illness 
• Before, during and after sport
• When planning pregnancy, during pregnancy and while breastfeeding 
• If awareness of hypoglycaemia is impaired 
• During high-risk activities.

Regulation and quality

In February 2015 the Health Products Regulatory Authority (HPRA) published a document entitled Safety notice: medical devices in the home.⁸ the document made a number of recommendations in relation to blood glucose monitoring aimed at those providing and using blood glucose meters.

In response to this publication, a newly established blood glucose monitoring review group advised the following best practices: 

• Registration and traceability of meters
• Quality control of meters
• Training for both the patient and the healthcare professional (HCP). 

Registration and traceability of meters

It is essential to register each capillary blood glucose meter with the manufacturer. This will provide: 

• Replacement by the company in the event of safety concerns
• Access to information regarding the safe use of capillary blood glucose meters
• Access to support materials provided by the manufacturer.

Registration can be achieved by:

• Completing the warranty card included in the meter packaging
• Using the freephone number provided in the meter packaging
• Registering online using the manufacturer’s website.

Quality control

HBGM results must be accurate and precise to ensure safety for patients. See Table 2 for a list of meters achieving ISO standards as of June 2017. Since the data for Table 2 was collated, the GlucoRX Nexus range (Ideal, Mini-Ultra and Voice) with Nexus test strips have also come on the market in Ireland, are CE marked and meet ISO 15197 standard. 

Table 3 lists older meters, some of which do not meet ISO 15197 standards and are no longer promoted by manufacturers, that are still in use by patients. Manufacturers recommend that quality control (QC) solutions must be used to ensure the meter is producing accurate results but, in practice, the use of QC solutions is minimal.

Training and education

Formal training in capillary blood glucose monitoring and the use of meters is essential for the person with diabetes, his or her carers, and the HCP. Patients using meters require access to a HCP deemed competent in the use of the meter.Training and education

Ideally, patients should have an assessment of their blood glucose self-monitoring technique as part of their annual review visit.⁹ However, elements of HBGM will form part of each consultation. This should include:

• The patient’s self monitoring skills
• Frequency of blood glucose testing and circumstances including pre driving as appropriate
• Checking that the patient can interpret the blood glucose results and know what action to take 
• The impact on the patient’s quality of life
• The continued benefit to the patient
• The equipment used
• The accurate recording of results or downloading of results to verify blood glucose readings.

It is generally recommended by the manufacturers that all blood glucose meters are replaced every two years.

Special circumstances to be considered¹⁰

Capillary blood glucose testing may not be appropriate for monitoring blood glucose in patients with:

• Poor peripheral perfusion
• Severe dehydration (diabetic ketoacidosis or hyperglycaemic hyperosmolar syndrome)
• Shock
• Peripheral arterial occlusive disease
• Lipaemic sample (triglycerides > 20.3mmol/L)
• Abnormally high/low haematocrit (low haematocrit < 10% may cause higher results; high haematocrit > 65%  may cause lower results)
• Continuous ambulatory peritoneal dialysis (depending on dialysate type used)
• Intravenous immunoglobulin preparations containing maltose.

A venous blood sample should be obtained from these patients instead.

Choice of equipment

There are a number of blood glucose meters available. The choice of a blood glucose meter for the person with diabetes will depend on a variety of factors, including size, ease of use and the type of strip (eg. canister, individual foil wrapped strip or strip free). 

Other additional features such as memory and download capability, alarms and back lights may need to be considered for some patients. Individuals with visual impairment or dexterity problems will need a meter that accommodates these issues. People with type 1 diabetes will require a meter to measure blood ketone levels, or a smart meter that assists in insulin bolus calculations. Patients using insulin pumps will require a meter that relays blood glucose levels to their pump. Thus, the choice of blood glucose meter needs to be tailored to each individual patient.

The meter and testing strips chosen must comply with the ISO 15197 standard and be CE marked to comply with performance standards specified by the manufacturer for intended purpose. It is recommended by manufacturers that meters are replaced every two years. 

Current and future developments

Recent developments in blood glucose monitoring have provided us with two new systems to measure interstitial glucose; continuous glucose monitoring (CGM) and flash glucose monitoring. These systems are expensive, and are currently only recommended for people with type 1 diabetes under certain conditions and should only be provided by a specialist centre with expertise in their use.

Continuous glucose monitoring

A sensor is inserted into the subcutaneous skin around the abdomen to which a transmitter is attached. This sends data wirelessly to a display device which shows real-time glucose information including trending. Interstitial glucose correlates well with plasma glucose, with some devices having alarms for hypo and hyperglycaemic excursions, reducing the need for capillary blood glucose sampling.

Flash glucose monitoring

This method of monitoring is becoming more popular. However, it has not yet been formally evaluated by NICE on clinical and cost-effectiveness grounds. The only licensed system in Ireland is the FreeStyle Libre, which is currently being reimbursed by the primary care reimbursement system (PCRS) on a trial basis for patients with type 1 diabetes up to the age of 21. 

It involves inserting a sensor, scanned with an individual patient reader or a smartphone app and replaced every 14 days, in the upper arm. When worn continuously, each scan gives the current interstitial glucose reading, a record of the last eight hours and shows which direction the glucose is trending. This is displayed numerically and in graph representation. It allows for unlimited scanning at no extra cost. This is a measurement of interstitial fluid glucose, not blood glucose and therefore there will be a discrepancy due to the known lag time of 5-10 minutes. See www.nice.org.uk/advice/mib110 for further reading.

It is noted that this technology does not completely replace capillary blood glucose monitoring. Patients will continue to require home blood glucose monitoring in addition to flash monitoring under the following circumstances:

• Blood glucose reading under 5mmol/L
• Blood glucose readings higher than 13mmol/L
• Before driving
• If feeling unwell.

Numerous studies have demonstrated the importance of optimal blood glucose control. HBGM is an excellent educational tool that provides an immediate glucose result. Indiscriminate testing by all patients with type 2 diabetes is not recommended. Efficient and cost-effective use of blood glucose monitoring equipment is essential. With the availability of numerous methods to monitor home blood glucose it is imperative that all HCPs are mindful of the appropriate choice of equipment to suit each individual as well as ensuring that standards of care in glucose monitoring are met. 

References on request