A conscious patient has a blood glucose of 3.2 mmol/L and feels shaky. What is the first action?

Give fast-acting carbohydrate, then recheck glucose after 15 minutes

A patient with type 1 diabetes is nil by mouth before surgery and asks if they can skip their insulin. What is correct?

Insulin is not simply stopped in type 1; seek advice and follow a management plan

Yes, skip all insulin while not eating

Give only fast-acting insulin and no background

Which set of signs suggests diabetic ketoacidosis?

High glucose, ketones, deep rapid breathing and a fruity breath odour

Low glucose, shakiness and sweating

Slow breathing and low temperature only

How should the word 'units' be written on an insulin prescription or record?

In full as 'units', never abbreviated

It does not matter how it is written

An unconscious patient with known diabetes is found with a very low blood glucose. What is the priority?

Treat the hypoglycaemia urgently using the appropriate route and get help

Give oral glucose tablets into their mouth

Part B4 of 8 Providing and Evaluating Care Chapter 48 of 75

Diabetes and Insulin Management Questions

NMC CBT diabetes practice: treating hypoglycaemia, never omitting insulin in type 1, recognising DKA, and worked scenario answers.

Start reading ← NMC CBT hub ~5 min read

By JobLabs Editorial · UK healthcare reference editorial team

· July 16, 2026 · Updated Jul 17, 2026 · 2 min read

Diabetes care in the CBT is mostly about two emergencies at opposite ends, hypoglycaemia and diabetic ketoacidosis, and one persistent safety point about insulin. Get those and most questions follow.

Hypoglycaemia: four is the floor

A blood glucose below 4 mmol/L is hypoglycaemia, and it is treated promptly, because untreated it can lead to seizures, unconsciousness and death. In a conscious patient you give fast-acting carbohydrate, recheck after 15 minutes, repeat if still low, and then give a longer-acting carbohydrate to stop it returning. Giving insulin, waiting to see, or offering a slow fatty meal are all wrong.

If the patient is unconscious, it becomes an emergency treated by the appropriate route, never by putting anything in the mouth of an unconscious person, alongside urgent help.

Never simply omit insulin in type 1

The most important insulin principle is that people with type 1 diabetes always need background insulin, even when they are not eating, for example before surgery. Without it they develop diabetic ketoacidosis. So insulin is adjusted under a plan, not stopped. A question that offers “skip the insulin while nil by mouth” is offering the dangerous answer.

Recognising DKA

Diabetic ketoacidosis presents with high glucose, ketones, thirst and frequent urination, nausea, abdominal pain, deep rapid breathing, and a fruity smell on the breath. It is a medical emergency, most often in type 1 diabetes, needing urgent treatment. Recognising it, and telling it apart from hypoglycaemia, is a common exam task.

The units rule

Finally, the same safety rule that appears in the numeracy chapters returns here: insulin is dosed in units, and “units” is always written in full. The abbreviations U and IU are misread as extra zeros and have caused fatal ten-fold overdoses. Next: sepsis recognition and escalation. Five diabetes scenarios first.

Sources & further reading

Key takeaway from Diabetes and Insulin Management Questions

Frequently asked questions

What blood glucose level defines hypoglycaemia?

A blood glucose below 4 mmol/L, often remembered as four is the floor. It is treated promptly with fast-acting carbohydrate, then rechecked, because untreated hypoglycaemia can cause seizures, loss of consciousness and become life-threatening.

Can insulin be omitted in a person with type 1 diabetes who is not eating?

No. People with type 1 diabetes always need some background insulin, even when not eating, because without it they develop diabetic ketoacidosis. Insulin is adjusted rather than stopped, and you seek advice rather than simply omitting it.

What are signs of diabetic ketoacidosis?

High blood glucose, ketones, excessive thirst and urination, nausea and vomiting, abdominal pain, deep rapid breathing, and a fruity smell on the breath. DKA is a medical emergency needing urgent treatment, most often in type 1 diabetes.

Check your understanding

Quick quiz: Diabetes and Insulin Management Questions

5questions. Click an answer to see the explanation. Your score is saved on this device only.

1
A conscious patient has a blood glucose of 3.2 mmol/L and feels shaky. What is the first action?
A glucose below 4 mmol/L in a conscious patient is treated with fast-acting carbohydrate, then rechecked after 15 minutes and repeated if still low, followed by longer-acting carbohydrate. Giving insulin would worsen it, waiting risks deterioration, and fatty food acts too slowly.
2
A patient with type 1 diabetes is nil by mouth before surgery and asks if they can skip their insulin. What is correct?
People with type 1 diabetes always need background insulin, even when not eating, or they develop DKA. Insulin is adjusted under a plan, not simply omitted. Stopping it, or making unplanned dose changes, is unsafe, so you follow guidance and seek advice.
3
Which set of signs suggests diabetic ketoacidosis?
DKA presents with high glucose, ketones, thirst, deep rapid breathing and a fruity smell on the breath, and is an emergency. Low glucose with shakiness and sweating describes hypoglycaemia instead, which is the opposite problem and treated differently.
4
How should the word 'units' be written on an insulin prescription or record?
Units is always written in full, because abbreviations like U or IU are misread as extra zeros and have caused fatal ten-fold insulin overdoses. This is a specific UK safety standard, and the CBT checks it directly.
5
An unconscious patient with known diabetes is found with a very low blood glucose. What is the priority?
Severe hypoglycaemia in an unconscious patient is an emergency treated by the appropriate route, not oral, since giving anything by mouth to an unconscious person risks choking, while getting urgent help. Waiting, or giving insulin, would be dangerous.