Category: Functional Medicine and Nutrition, Health Assessment Functional Medicine and Nutrition Consultant Sunshine Coast
If there is one conversation that happens more often than almost any other in my practice, it is this one: someone comes to me having already been told, more than once, that their blood tests are normal. And yet they feel — unambiguously, undeniably — unwell.
Fatigue that sleep does not resolve. Concentration that keeps slipping. Digestion that is never quite right. Hormonal symptoms that build through the luteal phase or worsen across perimenopause. A general sense of low resilience, of operating at reduced capacity, of not quite being themselves.
The tests say normal. The body says otherwise. That disconnect is real, and it is more common than conventional medicine has been willing to acknowledge.
What “normal” actually means on a standard blood test
Laboratory reference ranges are calculated from population data. They show where the majority of results fall across a large, heterogeneous group of people. A result that sits within range simply means it falls within the statistical distribution of that population — it does not mean that result is optimal for you, or that your body is functioning well at that level.
This matters significantly for several reasons.
First, the population used to establish reference ranges includes people across a wide spectrum of health status. A “normal” ferritin level, for instance, includes people who are fatigued and those who are not. Being in range does not tell you which group you are in.
Second, a result can shift meaningfully within the normal range over time — moving from the upper quartile toward the lower quartile — and this trend will not be captured or flagged. Standard pathology gives you a snapshot, not a trajectory.
Third, single markers in isolation rarely tell the full story. A result that looks unremarkable on its own can become clinically meaningful when viewed alongside other borderline markers, symptom patterns, and health history.
What standard testing often does not capture
Routine blood screening is excellent at identifying clear pathology. That is what it is designed for. It is not designed to detect:
- subtle nutrient insufficiencies that fall below the threshold for clinical deficiency but still impair function
- patterns in cortisol output across the day that disrupt energy, mood, and sleep
- early inflammatory activity that does not yet meet the threshold for diagnostic relevance
- microbiome imbalances influencing immune function, nutrient absorption, and hormonal clearance
- mitochondrial inefficiency — the cellular energy production problem that is central to many fatigue presentations
- blood sugar instability that does not reach diagnostic criteria for pre-diabetes but still produces significant symptoms
These are functional questions — questions about how well the body is working, not just whether it is diseased — and they require a different kind of assessment.
How I approach health markers differently
In functional medicine, I use what are called functional optimal ranges — reference intervals that are narrower than standard lab ranges and are derived from research on healthy, high-functioning populations rather than average population data. A thyroid result, for example, that sits within the standard range but at the lower end of it may still be relevant in the context of someone presenting with fatigue, cold intolerance, and cognitive slowing. I read markers in context, not in isolation.
I also look at patterns across multiple markers simultaneously — because health status is rarely determined by one value. The combination of borderline iron stores, a vitamin D level in the lower normal range, a slightly elevated hs-CRP (high-sensitivity C-reactive protein, a marker of low-grade inflammation), and a TSH trending higher over the past two years tells a very different story than any of those results would in isolation.
And I review the health timeline — when did this start, what else was happening at the time, how has it changed — because a snapshot makes much more sense when you can see the film it came from.
What to do if you feel unwell despite normal results
Start tracking patterns rather than waiting for the next test. Energy levels, sleep quality, digestive function, mood, cycle changes, headaches, skin reactivity — these correlations over time often reveal what a single blood draw cannot.
Consider whether your existing results may look different through a functional lens. What ranges is your practitioner using? Have trends been assessed? Have the markers been interpreted in context of each other and of your symptoms?
And if the investigation feels incomplete, trust that instinct. Being told everything is normal when you are clearly not well is not a reason to stop asking questions. It is a reason to ask different ones.
Told your tests are normal but still not feeling well?
Book a Discovery Call — a 20-minute conversation (not a consultation) to discuss what has been happening and whether a functional, investigative approach might offer the clarity you are looking for.
📍 Sunshine Coast | 🌐 www.drshelleycavezza.com.au 📞 0419 821 666 | ✉️ info@drshelleycavezza.com.au
This post is for educational purposes only and is not a substitute for personalised medical advice. Please consult your healthcare professional before making significant changes to your health routine.
