Stress Levels (Cortisol)
Cortisol is the body’s primary stress hormone, produced by the adrenal glands. It plays a vital role in regulating metabolism, blood pressure, immune response, and the sleep-wake cycle. While cortisol is essential for short-term stress adaptation, chronically elevated or suppressed levels can disrupt mood, energy, hormonal balance, and immune resilience. Persistently high cortisol may indicate chronic stress, overtraining, Cushing’s syndrome, or adrenal hyperactivity. Low levels may point to adrenal insufficiency or Addison’s disease. Measuring cortisol is crucial for understanding the impact of stress on overall health and performance.
Albumin
Albumin is the most abundant plasma protein in the body, produced by the liver. It helps maintain oncotic pressure (fluid balance within blood vessels) and transports hormones, fatty acids, and medications. Low albumin levels may reflect liver disease, kidney conditions (such as nephrotic syndrome), inflammation, or protein malnutrition. It is a key marker of both liver synthetic function and general nutritional status.
Alanine Transferase (ALT)
ALT is a liver enzyme involved in amino acid metabolism. It is released into the bloodstream when liver cells are damaged. Elevated ALT is a sensitive indicator of liver inflammation or injury and is commonly associated with conditions like hepatitis, non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease, and certain medications. It is one of the primary tests used to assess liver health.
Bilirubin
Bilirubin is a yellow pigment formed from the breakdown of red blood cells. It is processed in the liver and excreted in bile. Elevated bilirubin levels can cause jaundice and may indicate liver dysfunction, haemolytic anaemia, or bile duct obstruction. It is a valuable marker for assessing both liver and red blood cell turnover.
Total Cholesterol
Total cholesterol represents the combined levels of all types of cholesterol in the blood—HDL, LDL, and VLDL. While cholesterol is essential for hormone production and cell membrane integrity, elevated total cholesterol is associated with an increased risk of atherosclerosis and cardiovascular disease. This marker is most informative when analysed alongside HDL, LDL, and triglycerides.
HDL Cholesterol
High-Density Lipoprotein (HDL) cholesterol is often referred to as “good” cholesterol because it helps remove excess cholesterol from the bloodstream and transports it to the liver for excretion. Higher HDL levels are protective against heart disease and stroke. Low HDL is an independent risk factor for cardiovascular disease and metabolic syndrome.
LDL Cholesterol
Low-Density Lipoprotein (LDL) cholesterol is considered “bad” cholesterol due to its tendency to deposit in arterial walls, forming plaques that can lead to atherosclerosis. High LDL levels significantly increase the risk of heart attack and stroke. LDL is a key target in lipid-lowering strategies and cardiovascular prevention.
Urea
Urea is a nitrogen-containing waste product formed in the liver from protein metabolism and excreted by the kidneys. Elevated urea levels may indicate kidney dysfunction, dehydration, high protein intake, or bleeding in the gastrointestinal tract. Low urea may be seen in liver disease or malnutrition. Urea is commonly used alongside creatinine to assess kidney health.
Estimated Glomerular Filtration Rate (eGFR)
eGFR estimates how well the kidneys are filtering blood, based on serum creatinine, age, sex, and ethnicity. It is the primary marker for detecting and staging chronic kidney disease (CKD). A declining eGFR suggests worsening kidney function, even before symptoms develop.
Iron
Iron is essential for haemoglobin production and oxygen transport in the blood. Low iron levels may cause iron deficiency anaemia, leading to fatigue, cognitive decline, and reduced physical performance. Elevated levels may suggest iron overload disorders such as haemochromatosis. Iron tests help assess dietary intake, absorption, and systemic availability.
Unsaturated Iron Binding Capacity (UIBC)
UIBC measures the reserve capacity of transferrin—the main iron transport protein—to bind additional iron. It helps assess iron availability and is typically elevated in iron deficiency and reduced in iron overload. UIBC is interpreted alongside serum iron, TIBC, and transferrin saturation for accurate diagnosis.
Ferritin
Ferritin is the primary storage protein for iron. It reflects the body’s iron reserves and is one of the most sensitive markers for diagnosing iron deficiency before anaemia develops. Elevated ferritin levels can result from inflammation, infection, liver disease, or iron overload conditions. It is also an acute-phase reactant, so context is key.
Vitamin D (25-hydroxyvitamin D)
Vitamin D is a fat-soluble vitamin involved in calcium absorption, bone health, immune regulation, and mood balance. The 25-hydroxyvitamin D level is the most accurate indicator of vitamin D status. Deficiency is linked to osteoporosis, fatigue, depression, and increased susceptibility to infections. Supplementation is often recommended, especially during winter months in the UK.
hs-CRP (High Sensitivity C-Reactive Protein)
hs-CRP is a highly sensitive marker of systemic, low-grade inflammation. Even modest elevations are associated with increased cardiovascular risk, insulin resistance, and chronic disease. It is particularly useful in assessing inflammatory status in asymptomatic individuals and is frequently used in cardiovascular risk profiling.
Follicle Stimulating Hormone (FSH)
FSH is a pituitary hormone that regulates reproductive function. In women, it stimulates ovarian follicle development and oestrogen production. In men, it supports sperm production. Abnormal levels can indicate menopause, polycystic ovary syndrome (PCOS), or testicular dysfunction, and are useful in fertility assessments and hormone evaluations.
Free Triiodothyronine (FT3) & Free Thyroxine (FT4)
FT3 and FT4 are the active thyroid hormones responsible for regulating metabolism, energy production, and thermoregulation. FT3 is the more biologically active hormone, while FT4 serves as its precursor. Abnormal levels may indicate hypothyroidism or hyperthyroidism and are interpreted in conjunction with TSH to assess thyroid function.
Thyroid Stimulating Hormone (TSH)
TSH is secreted by the pituitary gland and stimulates the thyroid to produce FT3 and FT4. It is the most sensitive marker for assessing thyroid function. Elevated TSH typically indicates an underactive thyroid (hypothyroidism), while low TSH points to an overactive thyroid (hyperthyroidism).
Globulin
Globulin encompasses a range of blood proteins that support immune defence, inflammation control, and hormone transport. Abnormal globulin levels can reflect immune disorders, chronic infections, liver disease, or nutritional deficiencies. It is a key component of total protein and supports interpretation of immune and hepatic health.
Total Protein
Total protein is the combined measurement of albumin and globulin in the blood. It offers insight into nutritional status, liver function, and chronic inflammatory conditions. Abnormal levels can result from liver disease, kidney disorders, malabsorption, or immune-related conditions.
Gamma-Glutamyltransferase (GGT)
GGT is a liver enzyme involved in the metabolism of glutathione and the transport of amino acids. Elevated GGT levels may signal liver disease, bile duct obstruction, alcohol use, or medication toxicity. It is especially sensitive to alcohol-induced liver stress and is used to confirm hepatic involvement when ALP is elevated.
Alkaline Phosphatase (ALP)
ALP is an enzyme found in the liver, bones, and bile ducts. High ALP levels may suggest bile duct obstruction, liver inflammation, or bone disorders such as Paget’s disease or vitamin D deficiency-related osteomalacia. It is best interpreted with GGT and calcium or phosphate levels.
Triglycerides
Triglycerides are a form of circulating fat used for energy storage. Elevated levels are associated with metabolic syndrome, insulin resistance, and an increased risk of cardiovascular disease and pancreatitis. They are typically elevated by a high-sugar diet, alcohol, or obesity.
HDL % (HDL as a Percentage of Total Cholesterol)
HDL % indicates how much of your total cholesterol is made up of HDL, the protective cholesterol subtype. A higher percentage suggests a more favourable lipid profile and a lower risk of atherosclerosis and heart disease.
Non-HDL Cholesterol
Non-HDL cholesterol is calculated by subtracting HDL from total cholesterol. It includes all potentially harmful cholesterol types such as LDL, VLDL, and IDL. It is considered a stronger predictor of cardiovascular risk than LDL alone, particularly in people with elevated triglycerides.
Creatinine
Creatinine is a by-product of muscle metabolism, filtered by the kidneys. Elevated levels typically indicate reduced renal function, though levels may also vary with muscle mass. It is a core component of kidney function testing and used to calculate eGFR.
HbA1c (Glycated Haemoglobin)
HbA1c reflects the average level of blood glucose over the past 8–12 weeks. It is the primary marker for diagnosing and monitoring type 2 diabetes. Elevated HbA1c suggests poor long-term glucose control and increases the risk of cardiovascular, renal, and retinal complications.
Total Iron Binding Capacity (TIBC)
TIBC measures the blood’s maximum capacity to bind iron with transferrin. It provides insight into iron transport capacity and is typically elevated in iron deficiency and reduced in iron overload or inflammation.
Transferrin Saturation
Transferrin saturation represents the percentage of transferrin that is actually bound to iron. It is a useful measure for assessing iron sufficiency. Low values indicate iron deficiency, while high values may suggest haemochromatosis or liver disease.
Uric Acid
Uric acid is a waste product of purine metabolism, excreted by the kidneys. Elevated levels (hyperuricaemia) may lead to gout and kidney stones, while very high levels may be linked to kidney dysfunction or certain cancers. Persistent elevations should be evaluated, particularly in individuals with joint pain or metabolic syndrome.
Vitamin B12 (Total)
Vitamin B12 is crucial for red blood cell production, neurological function, and DNA synthesis. Deficiency can lead to anaemia, fatigue, neuropathy, and cognitive disturbances. Risk groups include vegetarians, older adults, and individuals with absorption disorders. Measuring total B12 helps identify functional deficiencies and support metabolic health.
Oestradiol
Oestradiol is the predominant form of oestrogen and plays a vital role in regulating the menstrual cycle, fertility, bone health, and cardiovascular function. In women, low levels may indicate menopause or hypothalamic amenorrhoea, while high levels can be seen in PCOS or oestrogen-dominant states. In men, elevated oestradiol may result from testosterone aromatisation or liver dysfunction.
Luteinising Hormone (LH)
LH is a pituitary hormone essential for reproductive health. In women, it triggers ovulation and supports corpus luteum function. In men, it stimulates testosterone production by the Leydig cells of the testes. LH is used in fertility assessments and to diagnose conditions like PCOS, primary ovarian insufficiency, or hypogonadism.
