Blood sugar and HbA1c: normal levels, prediabetes and how tests work
Why blood sugar matters for long-term health
Your blood sugar (also called blood glucose) is one of the most important numbers in your health.
When it’s in a healthy range, you tend to:
Have steadier energy through the day
Find it easier to manage weight and cravings
Protect your heart, blood vessels, brain, eyes and nerves over the long term
When blood sugar stays too high, for too long, it increases the risk of:
Type 2 diabetes
Heart disease and stroke
Nerve damage and numbness (neuropathy)
Kidney disease
Vision problems and eye disease
At Piko, we include fasting blood sugar and HbA1c in our health check panels because they give a powerful snapshot of your metabolic health and future risk. We don’t just hand over numbers – our doctors review your results and create a personalised protocol to help you improve or maintain healthy blood sugar levels.
The main blood sugar tests (and what they measure)
There are several different blood sugar tests, and each one tells you something slightly different.
You’ll see them called things like:
Blood sugar test / blood sugar level test / glucose test / glucose blood test
Fasting blood sugar / fasting blood glucose
HbA1c test / A1c test / a 1 c blood test (sometimes mistyped as hpa1c, h1abc, hb1ca, hca1c blood test)
Pregnancy glucose test / gestational diabetes test
Let’s break them down.
Fasting vs random vs HbA1c – what’s the difference?
1. Fasting blood sugar
Measured after not eating or drinking anything with calories for 8–12 hours
Shows how your body handles blood sugar in a “baseline” state
In many guidelines, you’ll see something like:
Normal fasting blood sugar / normal fasting blood glucose: roughly below around 5.5 mmol/L (100 mg/dL)
Prediabetes range: roughly from around 5.6 to 6.9 mmol/L (100–125 mg/dL)
Possible diabetes: around 7.0 mmol/L (126 mg/dL) or higher, usually confirmed with repeat testing
⚠️ Important: Exact cut-offs and “normal ranges” can differ slightly between labs and countries. Results should always be interpreted by a doctor who knows your full history.
2. Random / non-fasting blood sugar
A random blood sugar test is taken at any time of day, regardless of when you last ate. It’s less precise for diagnosis, but useful for:
Checking very high levels when someone has symptoms of diabetes
Monitoring known diabetes in some situations
Because it depends heavily on what you’ve just eaten, doctors rely more on fasting blood sugar and HbA1c for assessing long-term risk.
3. HbA1c – the “3-month average”
The HbA1c test (often written as A1c) is different from a standard blood sugar test:
It measures how much glucose has attached to your red blood cells
Because red blood cells live ~8–12 weeks, HbA1c reflects your average blood sugar over the last 2–3 months, not just that moment in time
Typical interpretation (again, approximate):
Healthy / normal HbA1c: generally below about 42 mmol/mol (6.0%)
Prediabetes (increased risk): roughly 42–47 mmol/mol (6.0–6.4%)
Possible diabetes: 48 mmol/mol (6.5%) or higher, usually confirmed with repeat testing or additional tests
Some people have small variations in HbA1c for reasons unrelated to blood sugar (such as certain types of anaemia), which is why your doctor will always look at the whole picture.
What is prediabetes – and why does it matter?
Prediabetes means your blood sugar levels are higher than normal, but not yet in the range of diabetes.
You might see this referred to as:
A1c prediabetes (HbA1c in the “borderline” range)
Impaired fasting glucose (fasting blood sugar above normal but not yet diabetic)
Diabetic blood sugar levels – used informally to describe being close to, or in, the diabetic range
The key points:
Prediabetes doesn’t always cause symptoms
It significantly raises the risk of developing type 2 diabetes, heart disease and stroke
The good news: it’s often a reversible window of opportunity
With the right changes in nutrition, movement, sleep, weight and stress, many people are able to:
Lower their HbA1c
Return to healthy blood sugar levels
Reduce the risk of future complications
At Piko, we see prediabetes as a warning light on the dashboard – a chance to act early, not a reason to panic.
What is considered a “good” or “healthy” blood sugar level?
People often ask: “What are healthy blood sugar levels?” or “What is a good blood sugar reading?”
There are a few different ways to think about it:
1. Lab reference ranges
Lab reports show a reference range – the values most people fall into. Being outside this range doesn’t automatically mean something is wrong, but it signals that your result needs interpretation.
2. Diagnostic cut-offs
For fasting blood sugar and HbA1c, guidelines set cut-offs for:
Normal / healthy
Prediabetes / increased risk
Diabetes
These cut-offs are used to trigger further testing and discussion, not to label you instantly based on a single blood test.
3. “Optimal” vs “just not diabetic”
From a longevity and prevention perspective, there’s a difference between:
“Not technically diabetic”, and
“Optimally low risk over decades”
Even if your numbers sit inside the “normal” range, your doctor may still suggest improving weight, movement, diet or sleep to keep them in the best possible zone for heart and brain health.
⚠️ Reminder: Any numbers you see online are general guidance. Always speak to your own doctor about your results and what they mean for you.
Risks of high blood sugar (even before diabetes)
Higher blood sugar is about much more than diabetes labels. Over time, it can:
Damage blood vessels – raising the risk of heart attack, stroke and circulation issues
Harm nerves – leading to numbness, tingling, pain, or problems with digestion and sexual function
Strain the kidneys – potentially leading to chronic kidney disease
Affect the eyes – increasing the risk of retinopathy and vision problems
Impact the brain – linked with cognitive decline and dementia risk in some studies
This is why we focus not just on “avoiding diabetes”, but on keeping glucose and HbA1c as healthy as possible over many years.
What about low blood sugar?
We talk a lot about high blood sugar, but low blood sugar (hypoglycaemia) is important too – especially in people who:
Use insulin or certain diabetes medications
Drink a lot of alcohol without food
Have underlying hormonal or metabolic conditions
Symptoms of low blood sugar can include:
Shakiness or trembling
Sweating
Feeling very hungry
Fast heartbeat
Anxiety, irritability or mood changes
Difficulty concentrating, confusion, or feeling “spaced out”
Severe low blood sugar can be dangerous and needs urgent attention.
Even in people without diabetes, frequent “sugar crashes” after high-carb meals can cause:
Energy swings
Cravings for more sugar
Trouble focusing
If you notice repeated episodes like this, it’s worth discussing with a healthcare professional.
Blood sugar in pregnancy – the pregnancy glucose test
During pregnancy, some women develop gestational diabetes – high blood sugar that appears for the first time during pregnancy.
To check for this, doctors may use:
A pregnancy glucose test (often an oral glucose tolerance test)
A gestational diabetes test at a specific week of pregnancy, especially if you have risk factors (such as higher BMI, family history, previous large baby, or certain ethnic backgrounds)
Gestational diabetes:
Often doesn’t cause obvious symptoms
Can increase the risk of birth complications if untreated
Raises the mother’s future risk of type 2 diabetes
The good news is that with early diagnosis and careful management, most women go on to have healthy pregnancies and healthy babies.
How Piko uses blood sugar and HbA1c in health checks
At Piko, we see blood sugar markers as central to energy, performance and longevity.
Our health check panels typically include:
Fasting blood sugar / fasting glucose – how your body handles sugar at baseline
HbA1c test – your 2–3 month average
Often lipids, liver enzymes, kidney function and inflammatory markers as part of a broader metabolic panel
We then layer these results with:
Your symptoms, lifestyle and medical history
Other markers like cholesterol, blood pressure, weight and waist circumference
Doctor-reviewed results
Instead of automatically generated comments, your results are:
Reviewed by a doctor experienced in interpreting metabolic health
Considered in context – not just “high” vs “low”
Used to identify where lifestyle changes could have the biggest impact
A personalised protocol – not just a PDF
Based on your blood sugar readings and overall blood work, your protocol may cover:
Nutrition tweaks to improve glycaemic control (e.g. fibre, protein balance, meal timing)
Activity and training suggestions to improve insulin sensitivity
Sleep, stress and recovery strategies
When and how to follow up with your GP or a specialist if numbers are concerning
The goal is simple: turn your blood sugar and HbA1c tests into a clear, practical plan to protect your heart, brain and metabolic health for the long term.
Where to go next
If you’re curious to learn more, you might also like:
Our explainer on metabolic panels and kidney function – how glucose fits into the bigger picture of organ health
Our guide to weight and metabolic health – how excess weight, visceral fat and blood sugar interact
Our overview of complete health checks – how blood tests, blood pressure and lifestyle assessment come together at Piko
Blood sugar doesn’t have to be a mystery. With the right tests, interpretation and support, it becomes one of the most powerful tools you have to stay energised today – and protect your health for years to come.
