What we test and why it matters

All cholesterol not carried by HDL particles. A stronger predictor of cardiovascular risk than LDL alone because it captures remnant cholesterol, the particles most likely to penetrate arterial walls and trigger plaque buildup.

High-density lipoprotein, often called the "good" cholesterol. Carries excess cholesterol from the arteries back to the liver for processing. Higher levels are associated with lower cardiovascular risk. Low HDL is a major independent risk factor, particularly when combined with high triglycerides.

Low-density lipoprotein, the primary carrier of cholesterol to cells. Elevated LDL is a key driver of atherosclerosis. Modern guidelines focus on LDL particle number and quality, not just the concentration measured in a standard test.

Fats stored in the blood that the body uses for energy. Elevated triglycerides are strongly linked to metabolic dysfunction, insulin resistance, and cardiovascular disease. The risk is especially pronounced when combined with low HDL. Diet, alcohol, and exercise are major influencers.

The combined measure of all cholesterol in your blood including HDL, LDL, and VLDL. Provides a starting point for cardiovascular risk assessment, but only meaningful when reviewed alongside the individual fractions. High total cholesterol driven by high HDL carries a very different risk profile than high LDL.

Each LDL, VLDL, and lipoprotein(a) particle carries exactly one ApoB protein. Testing ApoB directly counts the number of atherogenic particles in your blood, and is widely considered a more accurate cardiovascular risk marker than LDL cholesterol alone. Many leading cardiologists now regard ApoB as the gold standard lipid test.

Divides total cholesterol by HDL to produce a composite cardiovascular risk score. A ratio above 5 is considered elevated risk in Australian guidelines. Useful as a quick snapshot, best interpreted alongside ApoB and LDL particle data.

The balance between harmful and protective cholesterol. A ratio above 3.5 increases cardiovascular risk. Tracking this over time is more informative than any single reading, showing how diet, exercise, and medication are genuinely shifting your risk profile.

A genetically determined lipoprotein that carries cholesterol and is highly sticky, prone to depositing in arterial walls. High Lp(a) is an independent cardiovascular risk factor not affected by diet or standard lipid-lowering lifestyle changes. Roughly 1 in 5 Australians carry elevated Lp(a) without knowing. Testing once in your lifetime is recommended by major cardiology guidelines.

A calculated ratio of triglycerides to HDL that predicts cardiovascular risk more accurately than either measure alone. Reflects the overall balance of atherogenic versus protective lipoprotein particles. Strongly linked to insulin resistance and metabolic syndrome.

An amino acid produced during protein metabolism. Elevated homocysteine damages arterial walls and is a recognised independent risk factor for heart attack, stroke, and cognitive decline. Often driven by low B12, B6, or folate, and highly actionable with targeted supplementation. Also relevant for people with MTHFR gene variants.

The most liver-specific enzyme in a standard blood panel. Released into the bloodstream when liver cells are damaged or inflamed. Elevated ALT is a primary indicator of non-alcoholic fatty liver disease (NAFLD), hepatitis, and alcohol-related liver injury. Even mildly elevated ALT warrants follow-up.

Found in the liver, heart, and muscles. When elevated alongside ALT, this points to liver injury. The AST/ALT ratio provides additional clues: a ratio above 2 suggests alcohol-related liver disease. AST also rises after intense exercise due to muscle breakdown.

A sensitive marker for bile duct obstruction and alcohol-related liver damage. GGT is often the first enzyme to elevate in response to alcohol intake and can remain elevated for weeks after drinking stops. Also raised by certain medications and fatty liver disease.

The most abundant protein in blood plasma, produced almost entirely by the liver. Low albumin reflects reduced liver synthetic function and is a marker of chronic liver disease, malnutrition, or significant inflammation. Albumin also transports hormones, medications, and fatty acids through the bloodstream.

An enzyme found in the liver, bile ducts, and bones. Elevated ALP can indicate bile duct obstruction, liver disease, or bone disorders. Routinely elevated in children and adolescents during growth phases. When raised alongside other liver enzymes, it supports a diagnosis of cholestasis or bile duct blockage.

A yellow pigment produced by the breakdown of red blood cells, processed and excreted by the liver. Elevated bilirubin causes jaundice. High levels can indicate liver disease, bile duct obstruction, or haemolysis. Fractionating into direct and indirect bilirubin helps identify the underlying cause.

The primary measure of kidney filtering capacity, calculated from creatinine levels and adjusted for age, sex, and body size. A falling eGFR over time is the clearest signal of progressive kidney disease. Below 60 mL/min/1.73m2 for three months or more meets the threshold for chronic kidney disease.

A waste product from muscle metabolism that healthy kidneys filter efficiently. Elevated creatinine indicates reduced kidney function. Highly muscular individuals often have slightly higher creatinine without kidney disease, which is why creatinine is most useful when interpreted alongside eGFR. An important baseline for athletes taking creatine supplementation.

The kidneys regulate electrolyte balance. Abnormal sodium or potassium levels can reflect kidney dysfunction, adrenal disorders, or medication side effects. Electrolyte imbalances cause symptoms ranging from muscle weakness and fatigue to life-threatening cardiac arrhythmias. Critical monitoring markers for anyone on blood pressure medications or diuretics.

A waste product of protein metabolism filtered by the kidneys. Elevated urea alongside high creatinine confirms kidney impairment. Can also rise from dehydration, a high-protein diet, or gastrointestinal bleeding. The urea-to-creatinine ratio helps distinguish kidney disease from other causes of elevated urea.

The total amount of testosterone circulating in the blood, including protein-bound and free fractions. Relevant for both men and women. In men, low total testosterone is associated with fatigue, poor recovery, reduced libido, and loss of muscle mass. In women, both low and high levels drive symptoms, from low energy to PCOS-related changes.

The biologically active fraction of testosterone, not bound to SHBG or albumin, and therefore available to exert effects on tissues. Someone can have "normal" total testosterone but low free testosterone due to high SHBG levels, which explains symptoms that standard tests miss entirely.

A protein produced by the liver that binds to testosterone and estradiol, regulating how much of each hormone is biologically active. High SHBG lowers free testosterone availability. Low SHBG is associated with insulin resistance and metabolic syndrome. Essential context for interpreting any sex hormone result.

The primary oestrogen, critical for bone health, cardiovascular function, and reproductive health in both women and men. In women, tracks with the menstrual cycle and drops sharply at menopause. In men, small amounts are essential: too little impairs bone density, while too much causes water retention, mood changes, and feminisation.

Produced by the adrenal glands, DHEA-S is a precursor hormone the body converts into testosterone and oestrogen. Levels peak in early adulthood and decline with age. Low DHEA-S is associated with fatigue, low libido, and reduced resilience to stress. Elevated levels may indicate adrenal tumours or PCOS.

Released by the pituitary gland to trigger ovulation in women and testosterone production in men. Elevated LH in men with low testosterone points to primary hypogonadism (a testicular issue). Low LH alongside low testosterone suggests secondary hypogonadism (a pituitary or hypothalamic problem). In women, LH surges drive ovulation and are tracked closely in fertility assessments.

Stimulates follicle development in women and sperm production in men. High FSH in women indicates diminished ovarian reserve, a key marker assessed before IVF and in perimenopause. In men, elevated FSH can signal impaired spermatogenesis. Best interpreted alongside LH and AMH for a complete reproductive picture.

A 3-month average of blood sugar levels, and the gold standard for diagnosing and monitoring diabetes and pre-diabetes. Unlike fasting glucose, HbA1c isn't affected by what you ate the day before, making it more reliable for assessing long-term metabolic control. Also used to track how well diet and medication are working.

Blood sugar level after an overnight fast, providing a snapshot of baseline glucose regulation. Results between 6.1 and 6.9 mmol/L indicate pre-diabetes, a critical window where dietary and lifestyle intervention can prevent progression. Should be paired with HbA1c for a complete picture.

Measures the amount of insulin your body is producing. Elevated fasting insulin with normal glucose is the earliest sign of insulin resistance, where your pancreas is working harder to keep blood sugar in range. This is the stage where intervention is most effective, often years before HbA1c or glucose becomes abnormal.

A waste product from purine metabolism. Elevated uric acid causes gout but also independently predicts metabolic syndrome, kidney disease, and cardiovascular risk. High-fructose diets, alcohol, and red meat drive levels up. Increasingly viewed as a metabolic marker, not just a gout indicator.

The primary screening test for thyroid function. High TSH means your pituitary is working hard to stimulate an underactive thyroid (hypothyroidism). Low TSH suggests an overactive thyroid (hyperthyroidism) or indicates pituitary dysfunction. TSH alone misses the full picture, so Free T3 and Free T4 are needed to confirm actual thyroid output.

The main hormone produced by the thyroid gland. T4 is a prohormone that the body converts into the active T3 form in tissues. Low Free T4 confirms hypothyroidism and shows the thyroid isn't producing sufficient hormone, even when TSH is borderline. Essential for anyone on levothyroxine (Thyroxine) replacement therapy.

The active form of thyroid hormone that binds to receptors throughout the body. T3 is four times more potent than T4. Some people convert T4 to T3 poorly, meaning their TSH and T4 look normal while T3 remains low, a pattern that causes persistent fatigue, brain fog, and cold intolerance that standard testing misses entirely.

Antibodies that attack the thyroid enzyme responsible for hormone production. Elevated TPO antibodies are the hallmark of Hashimoto's thyroiditis, the most common autoimmune thyroid disease and the leading cause of hypothyroidism in Australia. Can be elevated years before thyroid function deteriorates, making early detection genuinely useful.

Antibodies targeting thyroglobulin, a protein involved in thyroid hormone production. Elevated TgAb, particularly alongside raised TPO antibodies, strongly suggests Hashimoto's thyroiditis or Graves' disease. Also used in thyroid cancer monitoring to ensure thyroglobulin measurements remain reliable after treatment.

The storage form of vitamin D and the most accurate way to assess your body's vitamin D status. Despite Australia's sunshine, deficiency affects roughly 1 in 4 Australians, particularly in southern states, office workers, and people with darker skin. Essential for bone health, immune function, mood regulation, and hormonal balance. Low levels are independently linked to depression, autoimmune disease, and increased infection risk.

Critical for nerve function, red blood cell production, and DNA synthesis. B12 deficiency is widespread, particularly among vegans, vegetarians, older adults, and people on metformin. Symptoms mimic depression and neurological disorders: fatigue, tingling in the extremities, poor memory, and mood changes. Deficiency can cause irreversible nerve damage if left untreated.

The main iron storage protein in the body and a far more sensitive marker of iron status than serum iron alone. Low ferritin causes fatigue, hair loss, poor exercise performance, and impaired cognitive function, even when haemoglobin is still within range. Very high ferritin can indicate iron overload (haemochromatosis) or significant inflammation.

Involved in over 300 enzymatic reactions, including energy production, muscle function, sleep regulation, and blood pressure control. Magnesium deficiency is extremely common but rarely tested. Symptoms include poor sleep, muscle cramps, anxiety, constipation, and migraines. Standard serum magnesium only reflects a fraction of total body magnesium, so many deficient individuals test within the "normal" range.

A B vitamin essential for DNA synthesis, cell division, and the production of red blood cells. Low folate causes megaloblastic anaemia and is a major risk factor for neural tube defects in pregnancy. Works closely with B12 in methylation pathways. People with MTHFR variants may require the methylated form (methylfolate) rather than standard folic acid.

A sensitive marker of systemic inflammation produced by the liver. The high-sensitivity version detects low-level chronic inflammation that standard CRP misses. Elevated hs-CRP above 3 mg/L independently predicts cardiovascular risk and is associated with metabolic syndrome, autoimmune conditions, and accelerated ageing. Best interpreted as a pattern over multiple tests rather than a single value.

Measures how quickly red blood cells settle in a tube, serving as a proxy for the presence of inflammatory proteins in the blood. A non-specific but useful general inflammation marker. Elevated ESR can indicate autoimmune conditions, infections, malignancies, or temporal arteritis. Less precise than hs-CRP for cardiovascular risk, but useful when assessing unexplained fatigue, joint pain, or fever.

A composite index calculated from platelet, neutrophil, and lymphocyte counts. Increasingly recognised as a powerful predictor of all-cause mortality and cancer prognosis. Unlike CRP, the SII reflects the balance of immune activity rather than a single acute-phase response. Elevated SII suggests immune dysregulation and systemic inflammatory burden.

The primary stress hormone, produced by the adrenal glands in a distinct daily rhythm. Highest in the morning and lowest at night. Chronically elevated cortisol drives abdominal weight gain, impairs immune function, disrupts sleep, and suppresses sex hormone production. Very low cortisol may indicate adrenal insufficiency. Best tested in the morning for meaningful interpretation.

A panel of tests that together reveal the full picture of iron status, including current circulating iron, total transport capacity, and how saturated the transport proteins are. Used alongside ferritin to diagnose iron deficiency anaemia, iron overload, and anaemia of chronic disease. Essential for anyone experiencing unexplained fatigue, particularly women of reproductive age and endurance athletes.

The most comprehensive single blood test available. Measures red blood cells, haemoglobin, haematocrit, white blood cells and their subtypes, and platelets. The FBC screens for anaemia, infections, bleeding disorders, leukaemia, and immune deficiencies. It's the essential starting point for any investigation into fatigue, recurrent infections, or unexplained bruising.

A ratio derived from the FBC that has emerged as a powerful systemic inflammation and immune stress marker. Elevated NLR indicates the immune system is in a heightened state, associated with chronic inflammation, poor surgical outcomes, and significantly increased all-cause mortality in population studies. A rising NLR over successive tests is a red flag worth investigating.

A screening test for autoimmune conditions. ANAs are antibodies that target the body's own cell nuclei. A positive result doesn't confirm autoimmune disease, but a high-titre positive, particularly with symptoms such as joint pain, fatigue, rashes, or hair loss, warrants further investigation for lupus, Sjogren's syndrome, or other connective tissue disorders.

The MTHFR gene produces an enzyme that converts folate into its active form, methylfolate, a process central to DNA repair, neurotransmitter production, and cardiovascular health. Common variants (C677T and A1298C) reduce enzyme activity, impairing methylation and raising homocysteine. Affects roughly 40-60% of the population to varying degrees. Highly actionable with specific supplementation protocols that compensate for impaired enzyme function.

The apolipoprotein E gene has three main variants: E2, E3, and E4. Carrying one or two copies of the E4 allele significantly increases lifetime risk for both Alzheimer's disease and cardiovascular disease. APOE4 carriers clear dietary fat and cholesterol less efficiently and respond differently to saturated fat intake. Knowing your APOE status allows for targeted, evidence-based dietary and lifestyle interventions.

Hereditary haemochromatosis is one of the most common genetic disorders in people of Northern European descent, affecting approximately 1 in 200 Australians. HFE mutations cause the body to absorb too much iron, progressively damaging the liver, heart, and pancreas. Early detection is straightforward and treatment (regular blood donation) is simple and effective. Symptoms often don't appear until significant organ damage has occurred.

A hormone that mediates many of the effects of growth hormone and serves as a reliable proxy for GH activity throughout the day. Low IGF-1 in adults is associated with poor muscle maintenance, fatigue, reduced bone density, and cognitive decline. High IGF-1 drives cellular growth, which is beneficial for muscle repair but linked to increased cancer risk at chronically elevated levels. Tracking IGF-1 is central to longevity medicine protocols.

A calculated marker derived from fasting triglycerides and fasting glucose. The TyG index is emerging as a highly accurate surrogate for insulin resistance, comparable to the gold-standard clamp method but achievable from a standard blood test. Strongly predictive of cardiovascular events and metabolic disease progression over time.

LDL cholesterol that has been damaged by free radicals. Far more atherogenic than standard LDL and a direct marker of oxidative stress and cellular ageing. Elevated levels are associated with accelerated plaque formation, endothelial dysfunction, and increased cardiovascular events. Driven by smoking, poor diet, chronic stress, and inadequate antioxidant intake.

A protein produced by prostate tissue. Elevated PSA can indicate prostate cancer, benign prostatic hyperplasia, or prostatitis. Prostate cancer is the most common cancer in Australian men. PSA screening is recommended annually from age 50, or from 40 for men with a family history. Establishing a baseline in your 40s is increasingly recognised as best practice in proactive men's health.

In men, chronically elevated prolactin suppresses testosterone production. High prolactin causes low libido, erectile dysfunction, and infertility. Elevation may indicate a benign pituitary tumour (prolactinoma), certain medications, or hypothyroidism. Often missed because it's not included in standard hormone panels, even when the symptoms it causes are the reason for testing in the first place.

A calculated ratio of total testosterone to SHBG that estimates the proportion of bioavailable testosterone. A practical alternative to directly measured free testosterone in some lab settings. Low FAI correlates with symptoms of androgen deficiency even when total testosterone appears within range, making it valuable for investigating low energy, mood, and libido in men.

The best available blood test for assessing ovarian reserve, how many eggs remain. AMH levels decline gradually with age and are not affected by the menstrual cycle or hormonal contraception, making it reliable at any point in the month. Relevant for anyone planning a future pregnancy, experiencing irregular cycles, or considering egg freezing. Low AMH doesn't mean infertility, but it informs decisions and timelines.

The hormone that rises after ovulation and sustains a pregnancy in early stages. Low progesterone in the luteal phase (days 18-22 of the cycle) indicates anovulation or luteal phase deficiency, and is a recognised cause of cycle irregularities, PMS, heavy periods, and implantation failure. Essential for understanding whether ovulation is actually occurring.

Elevated prolactin in non-pregnant women suppresses ovulation by inhibiting FSH and LH release. A common, under-investigated cause of irregular or absent periods, infertility, and unexplained galactorrhoea (nipple discharge). May be driven by a pituitary adenoma, hypothyroidism, or certain medications including antidepressants and antipsychotics.

A precursor to cortisol and androgens, produced in the adrenal glands. Elevated 17-OHP is a marker for congenital adrenal hyperplasia (CAH), which can present in women as irregular periods, acne, and excess body hair. Also used to investigate PCOS and cases of elevated testosterone where adrenal rather than ovarian origin is suspected.