Blood Glucose Levels In Children: What To Look For And When To Test

Blood glucose levels in Children

Monitoring blood glucose (sugar) levels is essential to managing your child’s diabetes effectively [1]. But if your child has diabetes, what should you look for, and what are the best ways to check their blood glucose levels?

In this guide, we will look at blood glucose levels in children — including the signs of high or low glucose levels, when you should be monitoring your child, and how to monitor them. Read on to learn how to monitor blood glucose levels in children and more.

Why monitoring blood glucose levels in children is important

The number of children and young people living with diabetes increases yearly [2]. In 2019, over a million children and adolescents (up to 19 years old) had type 1 diabetes [2]. 

When your child has diabetes, it can be worrying and challenging for the entire family. However, with insulin therapy, careful blood glucose monitoring and support, they can live active, long and fulfilling lives [3].

Regular glucose checks are vital for children living with diabetes [1]. 

Children and adolescents (0–19 years of age) with type 1 or type 2 diabetes are at risk of developing all of the complications seen in adults with diabetes [2]. If their blood glucose levels fall too low or become too high, they could develop health problems in the short term [2, 3]. They are also at risk of long-term diabetes complications, including cardiovascular, kidney and eye conditions [2, 3]. 

Monitoring your child’s glucose levels can help you actively manage their diabetes treatment, maintain their well-being and protect their future health [2, 3].

Learning to monitor your child’s blood glucose levels

Regular monitoring of your child’s glucose levels at home will help you recognise blood glucose patterns — and their relation to factors such as food, exercise, stress, school and illness [3]. 

There are different ways to monitor  your child's blood glucose levels so that you can adjust their insulin and achieve the best possible glycaemic control [3, 4].  

This diabetes management should always be individualised to consider your child’s age, needs and abilities [4]. For example, if your child is young, you will need to take the lead on monitoring their blood glucose levels and providing diabetes care [4]. However, as they grow older, you, the diabetes care team and your child will work together to ensure they gradually become more skilled and confident in managing their condition[4].

‘Normal’ blood glucose levels in children

When your child has diabetes, their diabetes care team will give them blood glucose targets to help them maintain their health and protect against diabetes complications in later life [5]. 

Careful diabetes management is important, but it’s also vital to remember that your child’s health is not just about their blood glucose data. Their glucose levels should always be considered part of their wider health and well-being — taking social, emotional and physical factors into account [5]. Your child’s diabetes care team can help — for example, they can guide you to help you and your child make healthy food choices and learn how nutrition can affect their diabetes [5]. 

It’s not unusual for blood glucose targets to lead to family stress and conflict. If diabetes management is a battle, parents, carers, and young people, and the diabetes team may need to compromise to maintain harmony [5]. 

Signs of high blood glucose levels in children

High blood glucose levels are called hyperglycaemia - also known as a ‘hyper' episode for short [2, 3].

Your child’s diabetes team will set your child targets for their blood glucose level, but generally, hyperglycaemia is over 7 mmol/l before eating or more than 9 mmol/l after a meal [5]. 

The signs and symptoms of hyperglycaemia include:

• Feeling very thirsty 
• Passing a lot of urine, going to the toilet at night or having more wet nappies in young children
• Feeling tired and weak
• Losing weight without trying
• Problems with vision 
• Problems concentrating 
• Nausea 
• Abdominal pain 
• Fruity smelling breath [6]

If left untreated, a hyper can develop into the serious complication of diabetic ketoacidosis DKA) [5]. Look out for:

• Nausea or vomiting
• Abdominal pain 
• Dehydration
• Hyperventilation (difficulty breathing),
• Confusion,
• Extreme drowsiness,
• Reduced level of consciousness,
• Sweet-smelling or fruity breath [3, 5, 6]

If you are worried about DKA, seek urgent medical care. 

Sign of low blood glucose levels in children 

A low blood glucose level is known as hypoglycaemia. Episodes of hypoglycaemia are often called 'hypos' for short. During hypoglycaemia, glucose in your child’s blood drops too low [2]. 

It’s important to be aware of the signs of low blood glucose levels in your child and treat them quickly with a fast-acting source of glucose, such as a sweetened drink, glucose tablets or sweets, because hypoglycaemia can be very dangerous [2].

Generally, a hypo is when your child's glucose is at or below 3.9 mmol/l [7]. 

However, they may develop symptoms as their glucose falls [7].

The signs and symptoms of hypoglycaemia in children are:

• Increased hunger
• Headache
• Nausea
• Tiredness
• Cold, sweaty, pale, shaky and unwell
• Confused, difficulty concentrating
• Blurred vision
• Behavioural disturbances, including irritability and crying
• Nightmares and restless sleep
• Slurred speech 
• Dizziness and unsteady on their feet
• Drowsy and difficult to rouse 
• Decreased consciousness and in rare cases, coma
• Seizure [7]

However, symptoms can be subtle and differ between children. Always err on the side of caution and speak to their diabetes team so that you are confident in recognising and treating hypos [5,7].

How to monitor blood glucose levels in children

In children, blood glucose testing has traditionally included home monitoring of glucose levels using capillary blood glucose tests, as well as regular blood tests to measure glycated haemoglobin (HbA1c) [1, 5]. 

However, continuous glucose monitors (CGM) are becoming more widely available and can improve diabetes management, decrease worry, and reduce the burden of care for some children living with diabetes [8].

Here are the three methods of monitoring blood glucose levels in children in more detail:

Using finger-prick tests to monitor glucose levels in children

Self-monitoring blood glucose levels (SMBG) allows you to measure your child’s glucose levels rapidly and accurately at home [4]. SMBG involves pricking your child’s finger using a lancet and a glucose meter to measure their blood glucose level like an adult would test themselves [4,5, 9]. 

You must follow a structured testing programme — four or more daily tests are necessary for children with type 1 diabetes [4, 5]. It’s vital to test more frequently if they are exercising or unwell [5].

The National Institute for Health and Care Excellence (NICE UK) recommends these target ranges for optimal glucose management:

• Fasting plasma glucose (such as after waking in the morning): 4–7 mmol/litre 
• Glucose level before meals: 4–7 mmol/litre
• Glucose level after meals: 5–9 mmol/litre 
• Glucose level for young people when driving: At least 5 mmol/litre [5]

Keeping the blood glucose levels towards the lower end of these ranges will help your child get the lowest possible HbA1c. However, this must be balanced against other factors, including the risk of their blood glucose becoming too low [5]. Again, blood glucose targets need to be individualised.

HbA1c testing

The HbA1c blood test gives a measure of your child’s average glucose over the previous two to three months [9]. [5]. 

The advised HbA1c target in the UK is typically 48 mmol/mol (or 6.5%) or lower [5,9] for most people, but a different target may be suggested for your child. Keeping their HbA1c as low as possible will help protect your child’s health and reduce their risk of developing diabetes complications. 

However, your child’s diabetes team will set an HbA1c target for them, considering their activities, any other illnesses and their risk of hypoglycaemia [5]. They will work with you to achieve this goal [5].

Continuous glucose monitoring (CGM)

Continuous glucose monitoring (CGM) monitors your child's glucose levels day and night [9, 10]. 

A small device is implanted, usually into their upper arm or abdomen, to read their glucose levels continuously [9, 10]. It uses a tiny sensor inserted under the skin to send glucose readings to a monitor, which can be read 24 hours a day so that you can see their glucose levels, spot patterns and identify highs and lows [9, 10]. Many devices will send warnings or alarms if they notice complications like hypoglycaemia [10].

Research shows that CGM benefits the health and quality of life of children with diabetes and their families [8, 11]. These include less pain and distress from finger-pricks, better diabetes control management, and less worry for parents or carers when the child is at school, with others, or asleep [8, 11].

However, CGM isn’t for every child living with type 1 diabetes. 

In research, some families noted that their children were worried about insertion and removal, and parents were concerned about accuracy and technical problems [8]. CGM can also be more expensive than traditional finger-prick testing, mainly if it isn't covered by medical aid/insurance or healthcare [8, 10]. 

Monitoring blood glucose levels in children can seem daunting if your child has just been diagnosed with diabetes — but with the help of your diabetes care team, you can learn how to manage the condition together.