What Do Your Blood Sugar Lab Results Actually Mean? (An Ontario Guide)
- Sandra Venneri
- 6 days ago
- 6 min read
You logged into your patient portal, found your lab results, and now you're staring at a page full of numbers and abbreviations — glucose, A1C, reference ranges — with no idea what any of it means for you.
You're not alone. This is one of the most common questions I hear in my practice, whether I'm sitting across from a client at Nutrition Bites or working with patients at a diabetes education centre. Finding your results is only step one. Understanding them is what actually helps you make decisions about your health.
Here's a plain-language breakdown of the two numbers people ask about most, using the diagnostic criteria set out by Diabetes Canada:
Fasting Blood Glucose
This measures the sugar in your blood after not eating for at least 8 hours (usually your morning bloodwork, before breakfast).
Normal: 3.9 – 5.5 mmol/L
Prediabetes (impaired fasting glucose): 6.1 – 6.9 mmol/L
Diabetes range: 7.0 mmol/L or higher, confirmed on a second test (Diabetes Canada – Screening for Diabetes in Adults)
A single high reading isn't a diagnosis on its own — it's a snapshot. Stress, illness, and even a poor night's sleep can nudge this number. But a pattern of elevated readings over time is what your care team is really watching for.
A1C (Hemoglobin A1C)
This one's different — it doesn't just show a single moment, it shows your average blood sugar over the past 2–3 months. That's why it's often considered a more reliable big-picture number (MedlinePlus – A1C Test)
Normal: 5.9% or below
Prediabetes: 6.0% – 6.4%
Diabetes range: 6.5% or higher (Diabetes Canada – Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome)
Diagnostic Criteria Chart for Blood Sugars (Normal, Prediabetes, Type 2 Diabetes)
Fasting Blood Sugar (FBS) mmol/L | Hemoglobin A1c % | |
Normal | 3.9-5.5 mmol/L | 5.9% or less |
Prediabetes or Impaired Fasting Glucose | 6.1-6.9 mmol/L | 6.0-6.4% |
Diabetes range | 7.0 mmol/L or higher confirmed on second test | 6.5% or higher |
*** Please note, that Gestational/Pregnancy, Type 1 and other forms of Diabetes do not use these criteria. The above is general information and it is best to seek advice from a medical provider who can diagnose you personally.
Why "Not Diabetic Yet" Isn't the Same as "Nothing to Watch"
Here's the part that gets missed the most: prediabetes isn't a waiting room where nothing is happening. It's an active warning sign. Diabetes Canada notes that prediabetes places you at meaningfully higher risk of developing type 2 diabetes and its complications — even though you haven't crossed the diagnostic line yet (Diabetes Canada – Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome)
And here's the number that surprises most people: research shows type 2 diabetes can be developing in the body for 4 to 7 years before it's actually diagnosed (Diabetes Canada – Screening for Diabetes in Adults). That's years of your body sending signals before a lab value officially crosses a threshold.
This is exactly why I tell clients: don't just look at whether you crossed a line — look at the direction you're moving.
Was your A1C 5.4% two years ago and now it's 5.9%? That's a trend, even though both numbers are technically "normal."
Has your fasting glucose gone from 5.0 to 5.7 to 6.0 over your last three annual bloodwork? That's a trajectory worth discussing with your doctor, not a reason to wait until you officially cross into a diagnosis.
Thresholds are useful for diagnosis. They're not the best tool for prevention. If your numbers are trending upward year over year — even while staying "in range" — that trend is information you can act on now, while you still have the most room to change course.
Why Diabetes Management Is a Job for a Specialist
Something most people don't know: there are Certified Diabetes Educators (CDEs) — dietitians, nurses, and pharmacists with specialized training and exam certification specifically in diabetes management. That credential exists for a reason. Diabetes isn't a "eat less sugar, move more" condition. It's genuinely complex.
diaTribe's well-known "42 Factors" list lays out just how many things can move your blood sugar up or down — food, sleep, stress, hormones, illness, medications, activity, and more (diaTribe – 42 Factors That Affect Blood Glucose). Some of these you can control. Many of them, you can't. That complexity is exactly why generic advice so often falls flat — it isn't built for your specific mix of factors.
In practice, access to that specialized support often takes a while. Endocrinologists are in high demand and typically have limited time per patient. So it's common for a GP or NP to monitor and manage someone's blood sugar for years before a referral to a CDE or a diabetes education centre happens — often once the condition has already become more complex, or because formal diabetes education was never part of the picture to begin with.
Diabetes Canada (a volunteer educator role I hold personally) is a solid, reputable source for general education. It's a good starting point. But general information can only take you so far — knowing the guidelines is different from knowing what actually works for your body, your schedule, and your specific pattern of highs and lows. That's what a CDE or dietitian who knows your circumstances can help sort out: which tools in the toolbox are worth your time, and which aren't going to have as much impact for you.
The Myth That Keeps People From Asking for Help
There's one belief I hear more than almost any other: "my numbers only go one way — up — and there's nothing I can do about it."
That's not true, and it's worth saying plainly because it's often the exact thing that stops people from reaching out. Blood sugar trends aren't a one-way street. With the right, personalized support, numbers can stabilize, and in many cases improve — it's just very hard to figure out which levers apply to you without help, given how many of those 42 factors are in play at once.
Believing the number can only get worse is a reason people wait. It shouldn't be.
So Your Numbers Are Trending the Wrong Way. Now What?
This is exactly where I see people get stuck. They get the number, they get a little scared, and then they do… nothing. No plan. No idea what to actually change at dinner tonight.
The truth is, you don't need to overhaul your entire diet or cut out carbs completely. You need a framework for how to eat carbs in a way that keeps your blood sugar steadier — without turning every meal into a math problem.
That's exactly why I wrote Carb Confident. It's built around my 4 Carb Rules™:
Never Carb Alone — pairing carbs with protein, fat, or fibre to slow the blood sugar spike
Carb With a Friend — smart pairing strategies for the carbs you already love
Carb Responsibly — portion awareness without obsessive tracking
When You Over-Carb, Move Your Muscles — using movement to help your body manage the aftermath
If your recent labs — or the trend behind them — left you with more questions than answers, this is the next step: a simple, sustainable way to actually do something about it, instead of just worrying about it.
Or, if you'd rather talk it through with someone directly, book a consult and we'll look at your specific results (lab work or Continuous Glucose Monitor-Libre FreeStyle, Dexcom G6/G7 sensors data), your trend, and the factors unique to you, together.
We also offer a specialized Pathway 3-session package with extra education & meal plan to help you with your blood sugars called Prediabetes & Diabetes Pathway.
This post is for general education and isn't a substitute for medical advice. Always discuss your individual lab results and trends with your doctor, dietitian, or Certified Diabetes Educator.
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