Blood Test Glossary
Your comprehensive guide to understanding blood test markers. Learn what each biomarker measures, why it matters, and what your results mean.
80 biomarkers across 6 categories
❤️Cardiometabolic Health(13 markers)
Apolipoprotein A1
The main protein component of HDL particles.
Apolipoprotein B
The main protein found in LDL and other atherogenic lipoprotein particles.
Apolipoprotein B/A1 Ratio
The balance between potentially harmful and protective cholesterol carriers.
HbA1c
Measures your average blood glucose over the past 2-3 months.
HDL % of Total Cholesterol
Measures the percentage of your total cholesterol that is HDL.
HDL Cholesterol
Measures "good" cholesterol that helps remove other forms of cholesterol from your bloodstream.
hsCRP (High-sensitivity C-reactive protein)
Measures low-level inflammation in your body.
LDL Cholesterol
Measures "bad" cholesterol that can build up in your arteries.
Lipoprotein (a)
A specialised type of LDL particle with genetic determinants.
Non-HDL Cholesterol
Measures all cholesterol types except HDL.
Random Glucose
Measures your blood sugar levels at time of testing.
Total Cholesterol
Measures the total cholesterol level in your blood.
Triglycerides
Measures levels of this type of fat in your blood.
⚡Hormone Health(17 markers)
Anti-Mullerian Hormone (AMH)
A hormone produced by the ovaries that indicates egg quantity.
Anti-TG (Thyroglobulin Antibodies)
Antibodies targeting thyroglobulin, a protein essential for thyroid hormone production.
Cortisol
The primary stress hormone produced by the adrenal glands.
D.H.E.A. Sulphate (DHEAS)
An adrenal hormone that serves as a precursor to sex hormones.
Estradiol (Oestradiol, E2)
Oestradiol (E2) is the most potent of the three forms of oestrogen. In women it is produced primarily by the ovaries and varies dramatically across the menstrual cycle. In men it is produced by aromatisation of testosterone in fat, brain, bone and other tissues. Australian pathology labs report E2 in pmol/L; older US-style ng/dL or pg/mL conversions are sometimes seen on imported reports.
Ferritin
Ferritin is the body's main iron-storage protein. The amount of ferritin circulating in blood reflects how much iron is held in tissue stores (mostly liver, spleen and bone marrow). Because ferritin is also an acute-phase reactant, levels can rise temporarily during infection or inflammation, which can mask underlying iron deficiency.
FSH (Follicle Stimulating Hormone)
A pituitary hormone that stimulates egg and sperm production.
FT3 (Free Triiodothyronine)
The unbound, biologically active form of T3, the most potent thyroid hormone.
FT4 (Free Thyroxine)
The unbound, biologically active form of T4, the main thyroid hormone.
LH (Luteinising Hormone)
A pituitary hormone that triggers ovulation and stimulates testosterone production.
Progesterone
A hormone produced mainly by the ovaries that prepares the uterus for pregnancy.
Prolactin
A hormone best known for stimulating milk production.
PSA (Prostate-Specific Antigen)
PSA is a protein produced by both healthy and cancerous prostate cells, measured in nanograms per millilitre (ng/mL). It is a screening signal — not a cancer diagnosis — used to decide whether further investigation (free PSA ratio, multiparametric MRI, biopsy) is warranted. Australian guidelines (RACGP, Cancer Council Australia) use age-adjusted thresholds rather than a single cut-off because PSA naturally rises with age as the prostate enlarges.
SHBG (Sex Hormone Binding Globulin)
SHBG (Sex Hormone Binding Globulin) is a glycoprotein produced by the liver that binds tightly to testosterone, dihydrotestosterone (DHT) and oestradiol. The portion of testosterone bound to SHBG is biologically inactive, so SHBG levels directly determine how much "free" (bioavailable) testosterone reaches tissues. Insulin and androgens lower SHBG; oestrogen, thyroid hormone and ageing raise it.
T4 (Thyroxine)
The main hormone produced by the thyroid gland.
Testosterone
Testosterone is the primary androgen (male sex hormone), produced mostly in the testes in men and in much smaller amounts by the ovaries and adrenal glands in women. Australian pathology labs report testosterone in nmol/L. Most circulating testosterone is bound to SHBG and albumin; only the small "free" fraction is biologically active. Levels follow a strong circadian pattern, peaking in the early morning, which is why diagnostic samples should be taken before 10 am.
TSH (Thyroid Stimulating Hormone)
TSH (Thyroid Stimulating Hormone) is produced by the pituitary gland and tells the thyroid how much thyroid hormone (T4 and T3) to make. It works on a feedback loop: when circulating thyroid hormone is low, TSH rises to stimulate more production; when thyroid hormone is high, TSH falls. Because the feedback loop is so sensitive, TSH typically changes before T4/T3 do — making it the single most useful screening test for thyroid dysfunction. Australian pathology labs report TSH in mIU/L (also written μIU/mL or mU/L — they are equivalent).
🩸Blood Health(16 markers)
Basophils (count and %)
A type of white blood cell involved in allergic reactions and inflammation.
Eosinophils (count and %)
A type of white blood cell involved in allergic responses and parasite defense.
ESR (Erythrocyte Sedimentation Rate)
Measures how quickly red blood cells settle to the bottom of a test tube.
Haematocrit
Haematocrit (also written HCT or PCV — Packed Cell Volume) is the percentage of whole blood volume made up of red blood cells. It is reported automatically as part of every Full Blood Count (FBC) and is one of the three core red cell parameters alongside haemoglobin and red blood cell count.
Haemoglobin
The oxygen-carrying protein in red blood cells.
Lymphocytes (count and %)
White blood cells that play a central role in immune responses.
MCH (Mean Corpuscular Haemoglobin)
MCH (Mean Corpuscular Haemoglobin) measures the average amount of haemoglobin inside a single red blood cell, expressed in picograms (pg). It is calculated automatically as part of a Full Blood Count (FBC) by dividing total haemoglobin by the red blood cell count. MCH works alongside MCV and MCHC to characterise the size and haemoglobin content of red blood cells, which is essential for diagnosing the type of anaemia present.
MCHC (Mean Corpuscular Haemoglobin Concentration)
The average concentration of hemoglobin inside red blood cells.
MCV (Mean Corpuscular Volume)
The average size of red blood cells.
Monocytes (count and %)
A type of white blood cell that can develop into macrophages.
MPV (Mean Platelet Volume)
The average size of platelets in the blood.
Neutrophils (count and %)
The most abundant type of white blood cell, which fights bacterial infections.
Platelets
Cell fragments essential for blood clotting.
Red Blood Cell Count
The total number of red blood cells per volume of blood.
Red Cell Distribution Width (RDW)
Measures the variation in size of red blood cells.
White Blood Cell Count
The total number of white blood cells in your blood.
🫀Vital Organ Functions(12 markers)
Albumin
The main protein in blood plasma, produced by the liver.
ALP (Alkaline Phosphatase)
An enzyme found primarily in the liver and bones.
ALT (Alanine Transaminase)
ALT (Alanine Transaminase, also written ALAT or SGPT) is an enzyme concentrated in the liver. When liver cells are damaged, ALT leaks into the bloodstream, so it is the single most liver-specific enzyme on a standard Liver Function Test (LFT). It is often interpreted alongside AST, GGT and ALP to build a picture of liver health.
AST (Aspartate Transaminase)
AST (Aspartate Transaminase, also written ASAT or SGOT) is an enzyme found in the liver, heart, skeletal muscle and red blood cells. Because AST exists in multiple tissues, it is less liver-specific than ALT. Pathology labs report AST as part of the standard Liver Function Test (LFT) panel.
Bilirubin
A yellow pigment produced during the breakdown of red blood cells.
BUN (Blood Urea Nitrogen)
A waste product filtered by the kidneys.
Creatinine
A waste product produced by muscles and filtered by the kidneys.
GGT (Gamma-Glutamyl Transferase)
An enzyme found in many tissues, especially the liver.
Potassium
An essential electrolyte for heart and muscle function.
Sodium
The main electrolyte in blood that regulates fluid balance.
Total Protein
The sum of all proteins in blood plasma, including albumin and globulins.
Uric Acid
A waste product from the breakdown of purines.
🥗Nutritional Status(12 markers)
Active B12
The biologically active form of vitamin B12.
Calcium
An essential mineral for bone health, muscle function, and nerve signaling.
Copper
A trace mineral essential for red blood cell formation and nerve function.
Folate (Vitamin B9)
A B vitamin essential for cell division and DNA synthesis.
Iron (Serum Iron)
Serum iron measures the amount of iron currently circulating in the bloodstream, bound to transferrin. It is a single snapshot in time and varies significantly by time of day (highest in the morning, lowest at night) and by recent meals. Serum iron is one of four results on the standard Australian iron studies panel — alongside ferritin (iron stores), transferrin / TIBC, and transferrin saturation — and is most useful when interpreted as part of the full panel rather than in isolation.
Magnesium
A mineral essential for over 300 biochemical reactions in the body.
Phosphate
An essential mineral that works with calcium for bone health.
TIBC (Total Iron Binding Capacity)
TIBC (Total Iron Binding Capacity) measures how much iron your blood could potentially carry if every transferrin binding site were saturated. Because transferrin is the main iron-transport protein, TIBC is an indirect measurement of transferrin levels and is reported as part of standard iron studies alongside serum iron, ferritin and transferrin saturation.
Transferrin Saturation
Transferrin saturation is the percentage of iron-binding sites on transferrin that are currently carrying iron. It is calculated as (serum iron ÷ TIBC) × 100 and is reported as part of standard iron studies in Australia. Of the four iron-studies markers, transferrin saturation is the most sensitive single test for haemochromatosis screening.
Vitamin B12
An essential vitamin for nerve function and blood cell formation.
Vitamin D (25-OH Vitamin D)
Vitamin D blood tests measure 25-hydroxy vitamin D (25-OH D), the main circulating form of vitamin D and the best indicator of overall vitamin D status. It reflects both sun exposure and dietary/supplement intake. Australian pathology labs report 25-OH vitamin D in nmol/L. Despite the name, vitamin D acts more like a hormone — it regulates calcium absorption, bone metabolism, immune function and roughly 200 genes throughout the body.
Zinc
A trace element essential for immune function and cell division.
🧬Methylation & Longevity(10 markers)
Active B12
The biologically active form of vitamin B12.
Cortisol
The primary stress hormone.
D.H.E.A. Sulphate
An adrenal hormone that declines predictably with age.
Folate (Vitamin B9)
Circulating levels of folate (B9), a critical methyl donor.
FT3 (Free Triiodothyronine)
The unbound, biologically active form of T3, the most potent thyroid hormone.
HbA1c
Measures your average blood glucose over the past 2-3 months.
hsCRP (High-sensitivity C-reactive protein)
Low-grade inflammation throughout your body.
T4 (Thyroxine)
The main hormone produced by the thyroid gland.
TSH (Thyroid Stimulating Hormone)
A pituitary hormone that regulates thyroid function.
Vitamin D
Circulating levels of vitamin D.
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