Your GP Said Your Bloods Are Normal. Here Are the 6 Markers They Never Actually Checked.
Written by Jessica Diakoumakos, Naturopath (BHSc Naturopathy & BHSc Psychology) · Emba Wellness, Melbourne · 2026
"Your results are normal." Most people have heard those words and still walked out feeling like absolute rubbish.
Standard pathology panels are designed to rule out disease — not to assess how well you're actually functioning. The six markers most commonly missing from a standard blood panel are: ferritin (stored iron), a full thyroid panel including Free T3, Free T4 and thyroid antibodies, fasting insulin, homocysteine, high-sensitivity CRP, and a complete sex hormone panel including SHBG. Each of these is well-researched, clinically meaningful, and routinely skipped in general practice.
Exhausted, foggy, hormonally all over the place — but apparently, everything looks fine on paper?
You're not alone. And honestly? This is one of the most common things I see in clinic.
The problem isn't that something is being missed on your blood test. It's that the right questions were never even asked.
Standard lab reference ranges are built on population averages — which, let's be real, includes a lot of people who are also exhausted and quietly struggling. Just because you fall within those ranges doesn't mean you're thriving. There's a significant difference between being "in range" and being optimal.
Functional medicine uses tighter, evidence-based reference ranges and — more importantly — a different set of questions. Instead of asking "do you have a diagnosable disease?", we ask "why does your body feel like it's running at 40%?"
Here are the six markers I look at that most GPs never order, and why each one matters.
Marker 1: Ferritin — And Why the Number Alone Isn't Enough.
Your GP probably does check ferritin. But here's where it gets interesting — a ferritin result on its own tells you surprisingly little without the rest of the iron studies panel alongside it.
Ferritin is your iron storage protein. But it's also an acute phase reactant, meaning it rises with inflammation. So you can have a ferritin that looks perfectly "normal" or even elevated — while your circulating iron is actually low, your transferrin saturation is tanking, and your cells are genuinely iron-deficient. Without serum iron, transferrin, and transferrin saturation alongside ferritin, the picture is incomplete.
(More on why the full iron studies panel matters — and how to read it — in an upcoming post.)
The other issue is the reference range. Conventional labs often set the lower reference limit for ferritin as low as 12–15 µg/L. A result of 14 µg/L is technically "within range." Functionally? It explains a lot.
Research shows ferritin below 40 µg/L is consistently associated with fatigue, hair loss, and impaired cognitive function in women — even with completely normal haemoglobin (Zhang, LaSenna & Shields, 2023). For energy and mitochondrial function, we want to see ferritin ideally above 50–80 µg/L. For hair loss specifically, studies recommend targeting above 70 µg/L (Zhang, LaSenna & Shields, 2023).
Here's the mechanism that rarely gets explained: iron is a critical cofactor in mitochondrial energy production — specifically in Complexes I, III, and IV of the electron transport chain. When iron stores are low, your cells literally cannot produce energy efficiently. No amount of sleep will compensate for a cellular energy shortfall.
The symptoms of low ferritin that get missed:
• Fatigue that doesn't improve with rest
• Hair thinning or diffuse shedding
• Brain fog — ferritin is required for myelin synthesis
• Poor exercise tolerance and breathlessness on exertion
• Restless legs — ferritin above 50–75 µg/L is the therapeutic target for RLS
• Worsening PMS or thyroid symptoms — iron is required for thyroid hormone conversion
Functional reference range:
Research supports treating ferritin below 40 µg/L in women with hair loss even without anaemia (Zhang, LaSenna & Shields, 2023). A 2023 study of female alopecia cases recommends redefining normal ferritin as ≥60 µg/L for early diagnosis of iron deficiency-related hair loss (Lin et al., 2023).
For general energy and mitochondrial function, most functional medicine practitioners target above 50 µg/L as a minimum.
Marker 2: A Full Thyroid Panel — Not Just TSH.
This one frustrates me more than almost any other. I cannot count how many times a client has come in having been told their thyroid is fine — and their only result was TSH.
TSH is a pituitary hormone. It tells your thyroid to produce hormones. It says nothing about how much active thyroid hormone is actually reaching your cells, and it tells you nothing about whether your immune system is attacking your thyroid.
A complete functional thyroid panel includes:
• TSH — both GP and naturopath check this
• Free T3 — the active form of thyroid hormone that your cells actually use
• Free T4 — the precursor; must be converted to T3 (conversion requires iron, selenium, and zinc)
• TPO antibodies — present in over 90% of Hashimoto's thyroiditis cases (Sifaki et al., 2025)
• Thyroglobulin antibodies (TgAb) — present in 60–80% of Hashimoto's cases
Why does this matter? Because Hashimoto's thyroiditis is the most common cause of hypothyroidism in developed countries — and it is an autoimmune condition that can be active for 3 to 7 years before TSH levels shift (Sifaki et al., 2025). During that entire window, a standard TSH test will come back normal. The antibodies, however, tell a very different story.
In euthyroid Hashimoto's (meaning TSH is still normal), research shows people commonly experience fatigue, cognitive dysfunction, depressive mood, and weight changes — driven by ongoing immune activation and elevated inflammatory cytokines, independent of thyroid hormone levels (Pałkowska-Goździk et al., 2024).
So when I see a client who is exhausted, gaining weight, losing hair, and feeling cold — and their GP tells them their thyroid is fine based on TSH alone — my very next question is: "But has anyone actually checked your antibodies?"
Marker 3: Fasting Insulin — Not Just Fasting Glucose.
Glucose can look completely normal for 10 to 15 years while insulin resistance quietly develops in the background. If we only look at glucose — which is what standard panels do — we will miss this entirely.
Insulin resistance means your cells have stopped responding effectively to insulin. Your pancreas compensates by pumping out more and more insulin to keep glucose in a normal range. Glucose stays "normal." But the compensatory hyperinsulinaemia is already doing damage.
Fasting insulin is what reveals this. Research shows insulin resistance is present in approximately 64–80% of women with PCOS (Diamanti-Kandarakis & Dunaif, 2012; Lerchbaum et al., 2021) — and that glucose alone is insufficient to identify it. Fasting insulin above 10–12 mIU/L is where I start paying close attention, and even elevated-normal insulin (above 7–8 mIU/L) in someone with PCOS symptoms warrants investigation.
Here's the mechanism that's rarely explained: high insulin suppresses SHBG (sex hormone binding globulin). Lower SHBG means more free, biologically active testosterone circulating in your blood. This is a key driver of the androgen excess symptoms in PCOS — the acne, the hair thinning on the scalp, the unwanted facial hair. You cannot understand that hormonal picture without checking fasting insulin.
Signs of insulin resistance:
• Energy crashes after meals (especially carbohydrate-heavy ones)
• Weight gain around the abdomen that doesn't shift despite diet changes
• PCOS — irregular cycles, acne, excess androgens
• Difficulty losing weight despite doing "everything right"
• Sugar cravings, particularly in the afternoon
• Feeling "hangry" if meals are delayed
Fasting Insulin reference range:
There is no universally agreed optimal range for fasting insulin — reference intervals vary between labs and populations, and major health organisations do not currently recommend routine fasting insulin testing.
Most functional medicine practitioners use fasting insulin above 10 mIU/L as a clinical flag, with HOMA-IR above 2.0 as the standard research cutoff for insulin resistance (Matthews et al., 1985).
What matters most is the trend and the clinical context — particularly in someone with PCOS symptoms, where even fasting insulin in the "normal" range warrants investigation alongside HOMA-IR.
Marker 4: Homocysteine — The Methylation Marker Nobody Talks About.
Homocysteine is an amino acid that builds up in the body when methylation is impaired. Methylation is your body's process for detoxification, neurotransmitter production, DNA repair, and — critically for hormonal health — oestrogen clearance.
Elevated homocysteine is a red flag for suboptimal folate, B12, and B6 status — but it's also a marker of how efficiently your biochemical pathways are actually running. You can have B12 and folate results that look normal on a standard panel while homocysteine tells a very different story about what's happening at a cellular level.
Why it matters clinically: elevated homocysteine is associated with increased cardiovascular risk (Refsum et al., 2004), depression and cognitive decline (Selhub, 2008), poor oestrogen metabolism, and — importantly for my client base — it tends to worsen significantly post-pill as the oral contraceptive pill depletes B6, folate, and B12, all of which are required to keep homocysteine in check.
homocysteine reference range:
The conventional threshold for hyperhomocysteinaemia is above 15 µmol/L — but research shows cardiovascular risk begins rising from approximately 9–10 µmol/L, well below this conventional cutoff (Refsum et al., 2006; D'Elia et al., 2025).
Most functional medicine practitioners target below 8 µmol/L as an optimal range, recognising that risk is graded rather than having a single hard cutpoint.
Someone with a homocysteine of 12 may be told they're fine — but functionally, their methylation pathways are already under meaningful stress.
Groups most at risk:
• Anyone who has recently stopped the oral contraceptive pill
• People with MTHFR gene variants (extremely common; affects folate metabolism)
• Those with a diet low in leafy greens, legumes, and animal proteins
• Anyone with digestive issues affecting B12 and folate absorption
Marker 5: High-Sensitivity CRP — Because Standard CRP Isn't Sensitive Enough.
Standard CRP (C-reactive protein) measures acute inflammation — the dramatic stuff, like an active infection or a flare of inflammatory disease. It's not sensitive enough to detect the low-grade, chronic, simmering inflammation that drives so much of modern ill-health.
High-sensitivity CRP (hsCRP) is a different assay. It's sensitive enough to detect the kind of chronic, low-grade systemic inflammation that develops quietly over years and underlies autoimmune disease, cardiovascular risk, hormonal disruption, depression, and gut dysfunction — long before standard inflammatory markers move.
For context on why this matters: a large-scale meta-analysis found that elevated hsCRP is associated with a significantly increased risk of cardiovascular events even when cholesterol levels are normal (Ridker, 2003). For my clients, I'm equally interested in it as a driver of hormonal problems — chronic inflammation suppresses ovarian function, disrupts the HPA axis, and is one of the reasons stress and gut issues can throw your cycle into chaos.
hsCRP reference ranges:
• Below 1.0 mg/L — optimal
• 1.0–3.0 mg/L — elevated risk; low-grade chronic inflammation is present
• Above 3.0 mg/L — high risk; significant inflammatory burden
This test is cheap, widely available, and almost never ordered without a specific reason. In functional medicine, we order it routinely — because knowing whether chronic inflammation is present changes every recommendation we make.
Marker 6: A Full Sex Hormone Panel — Including SHBG.
Ordering oestradiol alone and calling it a hormone panel is like checking your tyre pressure and calling it a car service.
A complete functional sex hormone panel includes:
• Oestradiol (E2) — ordered on the correct cycle day (typically day 2–5 for a baseline)
• Progesterone — tested on day 21 in a 28-day cycle, or 7 days before expected period
• Total testosterone — and ideally free testosterone
• DHEA-S — adrenal androgen; important for stress response and androgen excess
• SHBG — sex hormone binding globulin; the piece most panels leave out
• LH and FSH — especially important if cycles are irregular
SHBG is the piece that changes everything. It's a protein produced in the liver that binds sex hormones — including testosterone and oestrogen — and inactivates them. The amount of SHBG you produce determines how much of those hormones are actually free and biologically active.
High insulin drives SHBG down (see Marker 3 above). Lower SHBG means more free testosterone. More free testosterone means more androgen excess symptoms. This is the mechanism behind why PCOS and insulin resistance are so closely linked — and why you cannot understand someone's hormonal picture without looking at SHBG alongside everything else.
Results also need to be interpreted in context of the cycle day they were taken — oestradiol on day 3 and oestradiol on day 14 are completely different values that mean completely different things. Without that context, hormone results are almost meaningless.
"The most common thing I see in clinic is someone who has been told their results are fine for years — sometimes decades — while carrying a symptom picture that functional testing explains within a single consultation. The difference isn't better luck. It's asking better questions of the same blood test."
— Jessica Diakoumakos, Naturopath (BHSc Naturopathy & BHSc Psychology), Emba Wellness, Melbourne, Victoria
So Why Aren't GPs Ordering These?
It's not because your GP doesn't care. It's because the conventional medical model is built to detect and diagnose disease — not to optimise function in people who fall just below the diagnostic threshold.
Standard pathology panels are also partly governed by what Medicare will rebate. Many of these markers require either a specific clinical indication or private pathology to order. As a naturopath, I can request comprehensive functional panels through private labs — often without a referral — and interpret them through a different lens.
The goal isn't to find something wrong. It's to understand your individual biology well enough that every recommendation — nutritional, herbal, lifestyle — becomes targeted rather than a generic guess.
Frequently Asked Questions.
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A Melbourne naturopath can order a wide range of functional pathology markers through private laboratories including Nutripath, Healthscope, and IScreen. These commonly include ferritin (not just haemoglobin), full thyroid panels with Free T3, Free T4, TPO antibodies and TgAb, fasting insulin, homocysteine, high-sensitivity CRP, and a complete sex hormone panel including SHBG. Many of these can be ordered without a GP referral, and results are interpreted through functional — rather than conventional population-based — reference ranges.
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Conventional reference ranges are set statistically using the middle 95% of a tested population — which includes many people who are already unwell. Functional reference ranges are narrower and based on where research shows people perform optimally. For example, ferritin above 12 µg/L may be "normal" on a standard report, but functional medicine targets 50–80 µg/L for optimal energy and hair growth. The same blood test, interpreted differently, can reveal a very different clinical picture.
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Yes. TSH only reflects whether the pituitary gland is signalling the thyroid — it says nothing about Free T3, Free T4, or whether thyroid antibodies are present. Hashimoto's thyroiditis, the most common cause of hypothyroidism, can be actively progressing for 3 to 7 years before TSH shifts. During that time, TPO antibodies are elevated but TSH remains normal. Without antibody testing, Hashimoto's can be completely missed at this early, treatable stage.
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Glucose can remain normal while insulin resistance develops silently over many years. Signs that warrant fasting insulin testing include: PCOS or irregular cycles, difficulty losing weight despite dietary changes, energy crashes after meals, abdominal weight gain, afternoon sugar cravings, and acne or excess hair growth. A fasting glucose result within range does not rule out insulin resistance — fasting insulin and HOMA-IR are the more sensitive markers.
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Some of these markers can be requested through your GP with clinical justification, and may attract a partial Medicare rebate. For a comprehensive functional panel, a naturopath or functional medicine practitioner can order through private pathology labs. Costs vary but a full functional panel typically ranges from $150–$350 out of pocket. At Emba Wellness, pathology review and functional panel ordering is included in consultations, and we can advise on the most cost-effective way to get the markers you actually need.
Ready to Actually Understand What's Going On?
If you've been told your results are normal but you still feel like something is off — this is worth looking into.
At Emba Wellness, I run comprehensive functional pathology reviews and build personalised protocols based on your unique biochemistry — not a one-size-fits-all approach. If you're in Melbourne or anywhere across Australia, we offer online consultations.
You can also read more about how conventional vs functional B12 and vitamin D ranges work in this post: Optimal B12 & Vitamin D Levels in Australia: Why "Normal" Results Often Aren't Enough
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