Free Clinical Reference Guide

The 7 markers your doctor
never ordered

Standard blood panels test what is easy to bill. These 56 markers test what is actually driving your condition. Bring this to your next appointment.

8 condition categories — 56 specific markers — what each one reveals
Gut System Autoimmune Hormonal Energy Skin Brain Metabolic Cancer Environment
Category 01
Gut System

70% of your immune system lives in the gut lining. Every condition downstream — autoimmune, hormonal, neurological, metabolic — has a gut upstream. These are the markers that map it.

Zonulin
The only direct marker of intestinal permeability. Elevated zonulin means the gut lining has become permeable — allowing bacterial fragments and undigested proteins into the bloodstream. This is the upstream driver of most autoimmune and inflammatory conditions.
Critical
Calprotectin (stool)
Measures active gut inflammation. Elevated levels indicate inflammatory bowel conditions, SIBO, or immune activation in the gut lining. Most GPs never order this. It tells you whether the gut is actively inflamed right now.
Often missed
Comprehensive Stool Analysis
Maps the full microbiome — diversity, beneficial bacteria levels, pathogenic organisms, yeast overgrowth, parasites, and digestive enzyme function. A single stool test reveals what years of symptom management never uncovered.
Often missed
Organic Acids (urine)
Reveals bacterial and yeast overgrowth in the small intestine, mitochondrial function, neurotransmitter metabolism, and nutrient cofactor status — all from one urine sample. Virtually never ordered by standard medicine.
Often missed
Secretory IgA (stool)
The first line of immune defence in the gut. Low sIgA means the gut's immune barrier is depleted — leaving you vulnerable to infection, food reactivity, and ongoing inflammation. High sIgA indicates active immune response.
Upstream
H. pylori Antigen (stool)
Active H. pylori infection depletes stomach acid, disrupts nutrient absorption, and drives chronic inflammation. It is present in over 50% of the global population. Most people have no idea they are carrying it.
Critical
LPS Antibodies (blood)
Lipopolysaccharides are bacterial fragments that cross a permeable gut wall into the bloodstream, triggering systemic immune activation. Elevated LPS antibodies confirm gut-driven systemic inflammation — the upstream cause of joint pain, brain fog, and autoimmune flares.
Upstream
What to ask for at your next appointment
Ask your GP or functional practitioner for: zonulin, stool calprotectin, comprehensive stool analysis with parasitology, organic acids urine test, secretory IgA, H. pylori stool antigen, and LPS IgG/IgA/IgM antibodies. If your GP refuses, a functional medicine practitioner can order these privately.
Category 02
Autoimmune

The average time between autoimmune symptom onset and correct diagnosis is 4.3 years. These markers detect the immune process years before standard diagnosis — and identify the upstream trigger driving it.

ANA Panel (antinuclear antibodies)
Screens for autoimmune activity broadly — lupus, Sjögren's, scleroderma, mixed connective tissue disease. A positive ANA does not confirm a condition but flags that an immune investigation is needed. Most GPs only order this late in the process.
Critical
TPO and TG Antibodies
Thyroid peroxidase and thyroglobulin antibodies confirm Hashimoto's — the most common autoimmune condition globally. TSH can be normal for 7 years while antibodies are actively destroying the thyroid. This is the test your doctor is not ordering at your annual check.
Often missed
Anti-dsDNA
Specific marker for lupus (SLE). Elevated anti-dsDNA indicates active lupus flare and correlates with kidney involvement. Should be tested in anyone with unexplained joint pain, rashes, fatigue, and sun sensitivity.
Often missed
HLA-B27
Genetic marker associated with ankylosing spondylitis, psoriatic arthritis, reactive arthritis, and inflammatory bowel disease. Present in the majority of people with these conditions. A simple blood test that changes the diagnostic pathway entirely.
Upstream
Homocysteine
Elevated homocysteine indicates methylation impairment — the body's ability to process and clear waste, hormones, and inflammatory compounds. High homocysteine drives systemic inflammation and is a stronger cardiovascular risk marker than LDL cholesterol.
Often missed
hs-CRP (high sensitivity)
Standard CRP measures acute infection. High-sensitivity CRP measures chronic low-grade inflammation — the type that drives autoimmune conditions, cardiovascular disease, and cancer environment. Optimal is below 0.5. Most labs flag nothing below 5.
Critical
Zonulin
Gut permeability is the upstream driver in 68% of autoimmune cases. Zonulin confirms whether the gut is the origin of the immune activation. Addressing gut permeability is the first clinical step in every autoimmune protocol — before any immune suppression.
Upstream
What to ask for at your next appointment
Ask for: ANA with reflex panel, TPO antibodies, TG antibodies, anti-dsDNA, HLA-B27 (if joint or back symptoms), homocysteine, hs-CRP, and zonulin. If you have a diagnosis already, ask for the antibody count specifically — not just symptom management.
Category 03
Hormonal

A standard hormone panel tests 2 markers. A complete hormonal picture requires 7. The difference between those two panels is the difference between being told you are normal and understanding why you feel the way you do.

Free T3 and Reverse T3
TSH tells you how hard the pituitary is working. Free T3 tells you how much active thyroid hormone your cells are actually receiving. Reverse T3 tells you if T4 is being converted to the inactive form — leaving you exhausted despite normal TSH. These two markers explain years of unexplained symptoms.
Critical
DHEA-S
The adrenal reserve marker. Low DHEA-S confirms HPA axis dysfunction — the stress response system has been running on overdrive and is now depleted. DHEA-S declines before cortisol shows up abnormal on standard tests. It is the early warning signal most practitioners miss.
Often missed
Fasting Insulin
Insulin resistance is present for 10 to 15 years before glucose becomes abnormal. Fasting insulin catches it early. Optimal is below 5 mIU/L. Most labs flag nothing below 25. This single marker explains weight resistance, afternoon crashes, brain fog, and hormonal imbalance simultaneously.
Upstream
Estradiol to Progesterone Ratio
Estrogen dominance — too much estradiol relative to progesterone — drives weight gain, mood instability, heavy periods, fibroid growth, and breast tissue proliferation. Neither marker alone tells the story. The ratio does.
Often missed
SHBG (sex hormone binding globulin)
SHBG determines how much of your testosterone and estrogen is actually bioavailable to your cells. Low SHBG with normal total testosterone means very little free testosterone is reaching tissue. High SHBG means hormones are being bound and unavailable. Total hormone levels mean nothing without this context.
Often missed
Cortisol 4-point Saliva
A single morning cortisol blood test misses the daily cortisol rhythm entirely. A 4-point saliva test maps cortisol at waking, midday, afternoon, and evening — revealing whether you are spiking too early, crashing by noon, or running flat all day. Each pattern has a different clinical implication.
Critical
Free Testosterone
Total testosterone includes bound testosterone that cannot reach cells. Free testosterone is what your body actually uses. Men with normal total testosterone and low free testosterone experience every symptom of low testosterone — low drive, brain fog, poor recovery, mood decline — and are told their labs are fine.
Often missed
What to ask for at your next appointment
Ask for: Free T3, Reverse T3, DHEA-S, fasting insulin, estradiol, progesterone, SHBG, free testosterone, and a 4-point cortisol saliva test. If your GP only offers total testosterone and TSH, request a referral or access these privately through a functional practitioner.
Category 04
Energy / Mitochondrial

Mitochondria produce over 90% of your cellular energy. When they fail, every system downstream fails with them. None of these 7 markers appear on a standard blood panel. All of them are measurable. All of them are addressable.

Organic Acids — Mitochondrial Markers
Specific organic acid markers — including citric acid cycle intermediates and electron transport chain byproducts — reveal whether mitochondria are producing ATP efficiently. This is the only way to directly assess mitochondrial function without a biopsy. Virtually never ordered in standard medicine.
Critical
CoQ10 (ubiquinol)
CoQ10 is the essential carrier in the electron transport chain — the mechanism by which mitochondria produce ATP. Statin medications deplete CoQ10 by up to 40%. Low CoQ10 explains fatigue, muscle weakness, poor recovery, and cardiovascular symptoms in anyone on long-term statin therapy — and many who are not.
Often missed
NAD+ via Organic Acids
NAD+ is the primary fuel for mitochondrial ATP production. Depletion — driven by chronic stress, poor sleep, alcohol, and aging — directly reduces cellular energy output. Organic acid markers including kynurenic and quinolinic acids indicate NAD+ pathway status without expensive direct testing.
Upstream
Ferritin
Iron is required for oxygen transport to mitochondria. Low ferritin — even with normal haemoglobin — causes fatigue, brain fog, hair loss, poor exercise tolerance, and cold intolerance. Optimal ferritin is 70 to 150 ng/mL. Most labs flag nothing below 12. The gap between those two numbers is years of unexplained exhaustion.
Critical
Magnesium RBC (red blood cell)
Serum magnesium is meaningless — the body maintains serum levels by pulling magnesium from tissue. RBC magnesium measures intracellular status. Magnesium is a cofactor in over 300 enzymatic reactions including ATP synthesis, cortisol regulation, and sleep architecture. 74% of adults are deficient. Almost none know.
Often missed
Lactic Acid
When mitochondria cannot produce ATP aerobically, the body shifts to anaerobic metabolism — producing lactic acid as a byproduct. Elevated resting lactic acid indicates chronic mitochondrial insufficiency. It is also elevated in certain B vitamin deficiencies and thiamine depletion.
Upstream
Active B12 (holotranscobalamin)
Standard serum B12 measures total B12 including inactive forms that the body cannot use. Active B12 — holotranscobalamin — measures only what is bioavailable. You can have a normal serum B12 and a functionally deficient active B12. Deficiency drives fatigue, neuropathy, brain fog, and mitochondrial dysfunction.
Often missed
What to ask for at your next appointment
Ask for: organic acids urine test (mitochondrial panel), CoQ10 blood level, ferritin, RBC magnesium, resting lactic acid, and active B12 (holotranscobalamin). If you are on statins, CoQ10 testing is non-negotiable.
Category 05
Skin

Eczema, psoriasis, acne, rosacea, and hair loss are not skin conditions. They are internal conditions with a skin address. Treating the surface without testing the origin is why they keep returning.

Zonulin
Gut permeability is the upstream origin of most chronic skin conditions. A leaky gut allows bacterial fragments and food proteins into the bloodstream, triggering the immune response that surfaces as eczema, psoriasis, urticaria, and acne. No topical treatment reaches this origin.
Upstream
IgG Food Sensitivity Panel
IgG reactions are delayed — symptoms appear 24 to 72 hours after exposure, making them impossible to identify without testing. Common IgG triggers for skin conditions include gluten, dairy, eggs, soy, and nightshades. Standard allergy testing (IgE) misses these entirely.
Often missed
Histamine and DAO Enzyme
DAO (diamine oxidase) is the enzyme that breaks down histamine in the gut. Low DAO allows histamine to accumulate — causing flushing, hives, eczema flares, rosacea, headaches, and digestive symptoms. This is histamine intolerance. It is driven by gut dysfunction and is almost never tested.
Often missed
Zinc
Zinc is required for skin cell turnover, wound healing, sebum regulation, and barrier function. Deficiency drives acne, slow wound healing, hair loss, and immune vulnerability. It is depleted by chronic stress, poor gut absorption, and high sugar intake. Optimal plasma zinc is 80 to 110 mcg/dL.
Critical
Omega 3 to Omega 6 Ratio
The modern diet delivers an omega 6 to omega 3 ratio of approximately 20:1. Optimal is closer to 4:1. This imbalance drives chronic systemic inflammation — the upstream driver of every inflammatory skin condition. A simple blood test reveals your current ratio.
Upstream
Vitamin A (retinol)
Vitamin A is essential for epithelial cell production and differentiation — the process by which new skin cells form and shed correctly. Deficiency causes keratosis pilaris, dry skin, poor wound healing, and impaired barrier function. Fat malabsorption from gut dysfunction is the primary driver of deficiency.
Often missed
MTHFR Gene Variant
The MTHFR variant — present in approximately 40% of the population — slows methylation, impairing the body's ability to clear histamine, heavy metals, and excess estrogen. All three drive skin inflammation. This is a one-time genetic test that permanently changes the clinical approach to skin conditions.
Upstream
What to ask for at your next appointment
Ask for: zonulin, IgG food sensitivity panel (96 or 200 foods), serum histamine and DAO enzyme, plasma zinc, omega 3 index, retinol (vitamin A), and MTHFR genetic test. If your dermatologist only offers creams and biologics, this panel tells a different story.
Category 06
Nervous System / Brain

90% of serotonin is produced in the gut. The standard psychiatric model never tests the gut. These 7 markers explain depression, anxiety, brain fog, and cognitive decline through the biological upstream — not the psychological downstream.

Homocysteine
Elevated homocysteine is directly neurotoxic — it damages the blood-brain barrier, impairs myelin production, and accelerates brain atrophy. It is the most underused cardiovascular and neurological risk marker available. Optimal is below 7 micromol/L. Most labs flag nothing below 15.
Critical
MTHFR Gene Variant
MTHFR variants impair methylation — the process that produces dopamine, serotonin, and adrenaline from their precursors. Someone with a double MTHFR variant cannot methylate effectively regardless of diet. This single genetic marker changes the entire approach to treatment-resistant depression and anxiety.
Upstream
LPS Antibodies
Lipopolysaccharides crossing a permeable gut wall into the bloodstream trigger systemic immune activation that crosses the blood-brain barrier — causing neuroinflammation. This is the biological mechanism behind post-viral brain fog, post-COVID cognitive symptoms, and treatment-resistant depression. It is testable. It is addressable.
Often missed
Vitamin D (25-OH)
Vitamin D receptors are present throughout the brain. Deficiency is associated with depression, cognitive decline, multiple sclerosis, and poor immune regulation. Optimal is 60 to 80 ng/mL. Most labs flag nothing below 30. The UK average is below 20. This is not a supplement trend — it is a biological reality.
Critical
Active B12 and Folate
B12 and folate are the two primary methyl donors for neurotransmitter synthesis. Deficiency in either blocks the production of serotonin, dopamine, and norepinephrine at the enzymatic level. Prescribing antidepressants without testing these first is treating the output without addressing the input.
Often missed
Omega 3 Index (EPA + DHA)
The brain is 60% fat. DHA is the primary structural fat in brain cell membranes. A low omega 3 index — below 8% — is associated with depression, ADHD, cognitive decline, and poor nervous system recovery. Published data links low DHA to accelerated brain aging and increased dementia risk.
Upstream
Morning Cortisol
The cortisol awakening response — the spike in cortisol in the first 30 minutes after waking — is the primary driver of morning energy, cognitive readiness, and immune activation. A blunted morning cortisol response indicates HPA axis dysregulation and is directly correlated with burnout, depression, and poor working memory.
Often missed
What to ask for at your next appointment
Ask for: homocysteine, MTHFR genetic test, LPS antibodies, vitamin D (25-OH), active B12 (holotranscobalamin), red cell folate, omega 3 index, and morning cortisol. If you have been prescribed antidepressants without these being tested, request them before your next prescription renewal.
Category 07
Metabolic / Cardiovascular

Insulin resistance begins 10 to 15 years before a type 2 diabetes diagnosis. Standard cardiovascular panels miss the most predictive risk markers. These 7 markers reveal what has been building silently.

Fasting Insulin
The earliest insulin resistance marker available — detectable a decade before glucose becomes abnormal. Optimal fasting insulin is below 5 mIU/L. Most labs flag nothing below 25. This single test reveals whether weight resistance, afternoon crashes, PCOS, hormonal imbalance, and brain fog are being driven by an insulin problem nobody has named yet.
Critical
HbA1c and Fasting Glucose Combined
Neither marker alone tells the full story. HbA1c shows 90-day average blood sugar. Fasting glucose shows the current moment. Together they reveal whether blood sugar dysregulation is acute, chronic, or both. Optimal HbA1c is below 5.4%. Many practitioners accept up to 5.9% as normal — a range where insulin resistance is already established.
Upstream
ApoB
ApoB measures the total number of atherogenic particles in the blood — including small dense LDL, VLDL, and IDL. Total cholesterol and even LDL-C can be normal while ApoB is elevated, indicating high cardiovascular risk. ApoB is the most accurate predictor of atherosclerotic cardiovascular events. It is rarely ordered on a standard lipid panel.
Often missed
Lp(a) — Lipoprotein little a
Lp(a) is a genetically determined cardiovascular risk factor that is independent of diet and lifestyle. It is present in approximately 20% of the population and increases cardiovascular and stroke risk by up to 3 times. It needs to be tested once in a lifetime. Most people with elevated Lp(a) have never been told they carry it.
Critical
hs-CRP
Chronic low-grade inflammation is the common driver behind insulin resistance, atherosclerosis, metabolic syndrome, and type 2 diabetes. High-sensitivity CRP below 0.5 is optimal. Most labs accept anything below 5 as normal. The gap between 0.5 and 5 is years of metabolic dysfunction progressing undetected.
Upstream
Homocysteine
Elevated homocysteine is an independent cardiovascular risk factor that damages arterial walls, promotes clot formation, and impairs endothelial function. It is driven by B12, folate, and B6 deficiency — all addressable. It is a stronger predictor of cardiovascular events than LDL in multiple published studies.
Often missed
Triglyceride to HDL Ratio
A triglyceride to HDL ratio above 2.0 is one of the most reliable proxy markers for insulin resistance — requiring no special test, just calculation from a standard lipid panel. A ratio above 3.0 indicates significant metabolic dysfunction. Most practitioners report the numbers separately and never calculate the ratio.
Upstream
What to ask for at your next appointment
Ask for: fasting insulin, HbA1c, fasting glucose, ApoB, Lp(a) — once in your lifetime, hs-CRP, and homocysteine. Then calculate your triglyceride to HDL ratio from your existing lipid panel. If your GP has never ordered fasting insulin, that conversation starts today.
Category 08
Pre-Cancer / Cancer Environment

Cancer does not start in the organ. It starts in the environment the organ is living in — built over years through chronic inflammation, impaired DNA repair, and immune surveillance failure. These markers map that environment before it becomes a diagnosis.

hs-CRP
Chronic inflammation is the single most consistent upstream driver of cancer development. hs-CRP below 0.5 indicates a low inflammatory environment. Sustained elevation above 2.0 indicates a biological environment in which DNA damage accumulates faster than it is repaired — the cancer precursor environment.
Critical
Homocysteine and MTHFR
DNA repair requires methylation. MTHFR variants that impair methylation reduce the body's capacity to repair DNA damage — the primary mechanism by which environmental damage becomes cellular mutation. Elevated homocysteine combined with an MTHFR variant is a significant cancer environment marker.
Upstream
Fasting Insulin
Cancer cells preferentially metabolise glucose — the Warburg effect. Elevated insulin creates a high-glucose, high-growth-factor environment that promotes cancer cell proliferation. Normalising fasting insulin is one of the most evidence-supported interventions for reducing cancer recurrence risk after remission.
Critical
Vitamin D (25-OH)
Vitamin D regulates over 200 genes involved in cell growth, differentiation, and apoptosis — the process by which damaged cells are eliminated before they can become cancerous. Optimal vitamin D is 60 to 80 ng/mL. Levels below 30 are associated with significantly elevated risk across multiple cancer types.
Often missed
Ferritin
Both low and high ferritin carry cancer risk. Low ferritin impairs immune surveillance. Elevated ferritin — above 200 in women and 300 in men — is an inflammatory marker associated with accelerated oxidative stress and iron-mediated cellular damage. It is also an early marker of several cancers including liver, colon, and lymphoma.
Upstream
Estradiol
Estrogen dominance — excess estradiol relative to progesterone — promotes proliferation of estrogen-sensitive tissue. This is the upstream driver of breast, endometrial, and ovarian cancer environment. Estradiol should be tested in all women with breast cancer history, fibroid growth, or hormonal symptoms — not just reproductive concerns.
Often missed
8-OHdG (oxidative DNA damage)
8-hydroxydeoxyguanosine is a direct marker of oxidative DNA damage — the mechanism by which free radicals cause mutations that initiate cancer. Measurable in urine. Elevated 8-OHdG indicates the DNA repair system is overwhelmed. This marker predicts cancer risk years before any structural change is visible on imaging.
Often missed
What to ask for at your next appointment
Ask for: hs-CRP, homocysteine, MTHFR genetic test, fasting insulin, vitamin D (25-OH), ferritin, estradiol, and 8-OHdG urine test. If you are in remission, these are the markers that tell you whether the environment that created the cancer has been addressed — or whether it is still present.

Your labs came back normal.
These markers were not ordered.

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