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Biomarkers A-Z

We test over 70 essential biomarkers which have an effect on your health, wellbeing and performance. You can look at each of the biomarkers here and find out what it is and the effects this can have when it’s out of a normal range.

Active B12

Vitamin B12 is absorbed by the body through diet and is often measured alongside folate. Like folate it has an important role to play in the production of healthy red blood cells but also has a function in nerve health. Both vitamin B12 and folate should be kept within the normal range to avoid different forms of anaemia and therefore to keep energy levels at normal levels. Deficiencies in B12 can lead to anaemia.

Alanine Aminotransferase (ALT)

Alanine aminotransferase (ALT) is an enzyme found mostly in the liver. Only small amounts are usually found in the blood. However, if the liver or your muscles are damaged an increased level of ALT will be released into the bloodstream. ALT can therefore be elevated due to excessive alcohol and also after strenuous exercise. To keep your liver healthy keep your alcohol intake within recommended guidelines and include nutrient dense sources of food such as wholegrains, fruit and vegetables in your diet.


Albumin (ALB) is a protein made in the liver which circulates in the blood. The amount of albumin in the blood is directly associated with liver function and nutritional health. Low levels are associated with problems in the liver or kidneys and is also linked to severe inflammation. A decreased level of albumin is also apparent when your body cannot absorb nutrients sufficiently, for example in low protein diets. Higher than normal levels can indicate dehydration. As albumin has a key role in the transportation of calcium it can also be used as a marker in the assessment of bone health.

Alkaline Phosphatase (ALP)

Alkaline phosphatase (ALP) is an enzyme found in several tissues including the liver, bone, kidney and bowel. High levels are most commonly associated with problems in the liver or bone. Levels of ALP can also increase when the body is healing fractures or during pregnancy. To ensure your levels are in the healthy range eat a healthy diet and keep alcohol intake within recommended guidelines. Try and balance your overall energy intake according to your body’s requirements and eat a high level of nutrient rich foods such as wholegrains, fruit and vegetables.


Basophils help to protect the body against infection and make up 1% of the total white blood cell count. An abnormal increase in the level of basophils can indicate an infection or inflammation which can leave you feeling tired and weak. A low count can be expected as they are the least abundant white blood cell in the body. Even if your result is low, your immune system may still be working effectively. You can improve the efficiency of your immune system by ensuring sufficient intake of micronutrients such as zinc, iron, vitamin A, C and E and by staying well hydrated.

Bicarbonate (C02)

Bicarbonate is an electrolyte which helps to regulate the pH balance of the body. It is secreted and absorbed by the kidney and helps to neutralise the acids that build up in the body as normal by-products of metabolism. Low levels can occur through sweating during intense exercise or during periods of diarrhoea and vomiting. These lost stores can be replenished through electrolyte drinks. Bicarbonate results should be evaluated alongside other electrolyte markers (sodium, chloride) to give a fuller picture of any electrolyte imbalances and acid base status.

Bilirubin (Total)

Bilirubin is produced by the liver when breaking down red blood cells and only small amounts are normally present in the blood. Bilirubin levels increase if too many red blood cells are destroyed or if the liver cannot remove bilirubin from the blood fast enough which can result in jaundice. Raised levels of bilirubin can also be caused by a hereditary condition called Gilbert’s syndrome or through excessive alcohol. To keep your levels in the healthy range keep within the recommended guidelines for alcohol and ensure a good balanced diet rich is natural food sources rather than processed food.


There is more calcium in the body than any other mineral. It has several important functions including helping to build and maintain strong bones and teeth, regulating muscle contractions and ensuring the blood clots normally. Because the majority of measured calcium is bound to proteins your corrected calcium result should be used for interpretation. You can improve your calcium levels through foods such as milk, cheese and green leafy vegetables such as broccoli and cabbage.


Chloride is an important mineral and helps to maintain the body’s pH balance by regulating the amount of fluid inside and outside of cells. It plays a role in digestion as well as helping to maintain blood pressure and blood volume. High concentrations of chloride can result in fluid retention and may also cause an increase in blood pressure in some cases. Chloride levels will fall when the body loses a lot of fluids which can happen after exercise. It is therefore important to rehydrate using isotonic drinks as well as water which help to replace lost chloride and sodium.

Cortisol (9am)

Cortisol is a steroid hormone and is released when the body feels under stress. Anxiety, a resticted diet or over-training can all cause cortisol levels to rise. Levels can also be influenced by infection, trauma or problems with the pituitatry or adrenal gland. High levels of cortisol can lead to increased blood pressure, high blood sugar levels, muscle weakness and weight gain. Low levels can lead to fatigue, low blood pressure, weight loss and muscle weakness.

Creatine Kinase

Creatine Kinase (CK) is an enzyme found mainly in the brain, skeletal muscles and heart. It has an important role to play in energy production and muscle contraction. When muscles are damaged CK leaks into the blood stream. Levels can therefore become raised due to injury or stress to muscle tissue particularly after exercise but should return to normal after a recovery period.


Creatinine is a waste product which is produced from creatine, a compound which has a major role in the production of energy needed for muscle contraction. The level of creatine produced will vary according to body size and muscle mass. Creatinine is removed from the body by the kidneys and released in urine. The levels of creatinine in blood is therefore a good indication of kidney function.


eGFR is used as an indication of how well your kidneys are functioning. Testing GFR directly is complicated, levels are therefore estimated based on your creatinine levels. Results can be influenced by a number of factors including muscle mass and weight. Individuals with high muscle mass will have higher levels which may be outside the normal range, and vise versa for individuals with low muscle mass. Creatinine and eGFR levels will rise immediately following strenuous exercise but should then return to baseline following recovery.


Eosinophils protect the body by responding to allergies and by resisting some infections. Raised levels can be associated with allergy or parasitic infection. Eosinophils only make up a small percentage (1-3%) of the total white blood cell count. You can improve the efficiency of your immune system by staying hydrated and ensuring a balanced diet with a high intake of fruit and vegetables such as tomatoes and carrots, together with herbs and spices e.g tumeric and cumin.


The amount of ferritin in the blood reflects the total level of iron stored within your body. Ferritin levels can be raised due to inflammation. Very high levels of ferritin indicate a large build up of iron in the body which can be due to a hereditary condition called haemochromatosis. Low ferritin levels are often caused by iron deficiency which can lead to anaemia and the production of small red blood cells. The best source of iron comes from red meat which ideally should be eaten at least once a week. For those following a vegetarian or vegan diet good plant sources include green leafy vegetables, seeds, beans and dried fruit.

Folate (serum)

Folate is not produced by the body but is supplied through diet. It plays an important role in the formation of healthy red blood cells as well as the repair of tissues. The folate test is useful in the evaluation of anaemia. Low levels may indicate a degree of deficiency.

Follicle Stimulating Hormone (FSH)

Follicle stimulating hormone (FSH) regulates the functions of the reproductive system. In women, FSH stimulates follicle growth in the ovary before the release of an egg, while in men FSH stimulates the production of sperm. Low levels of FSH can therefore cause fertility problems in both men and women and can indicate a malfunction in the ovaries or testes.

During the menopause/peri-menopause FSH and LH levels in women will rise: FSH between 13-25.8 and LH result higher than your FSH level is suggestive of perimenopause. FSH above 25.8 is consistent with perimenopause/menopause. FSH <13 is not suggestive of the menopause but diagnosis should be made on the basis of symptoms.

Free Androgen Index

Free androgen index (FAI) is an estimate of the amount of free testosterone in the bloodstream. It is calculated using the test results of testosterone (total) and sex hormone-binding globulin (SHBG). Low levels in men can lead to a low libido, while high levels in women can lead to the growth of facial and body hair as well as fertility problems.

Gamma GT

Gamma GT (GGT) is an enzyme, which is predominantly found in the liver. GGT levels can increase if the liver is damaged or if there is a blockage obstructing the flow of bile. The GGT test is extremely sensitive and can be elevated due to many reasons including the consumption of alcohol or other drugs/medication. To keep levels within the healthy range limit your consumption of alcohol to within the recommended guidelines and eat a healthy balanced diet.


Globulin is a general term used to describe more than 60 proteins found in the blood. If globulins are not within the correct level this can impair the body’s ability to fight infection, clot or carry nutrients to the muscles. Low and high levels are associated with a wide range of health conditions including problems with the bowel, kidney or liver. To keep levels within the healthy range limit your consumption of alcohol to within the recommended guidelines and eat a healthy balanced diet.

Haematocrit (HCT)

The haematocrit (HCT) test measures the volume of space in your blood which is made up of red blood cells. Low levels can suggest anaemia which means that an insufficient supply of oxygen is reaching your tissues resulting in a loss of energy. The main nutrient for all red blood cells is iron. As the best source of iron is red meat, those following a vegetarian or vegan diet may find it harder to absorb adequate quantities.


Haemoglobin is a protein found in blood. Its role is to carry oxygen to cells throughout the body and return carbon dioxide back to the lungs. A low level can indicate anaemia and may result in reduced energy. Anaemia has many causes including nutritional deficiency. By improving your haemoglobin you can improve your organ and tissue functions and increase your overall energy levels. High haemoglobin levels are indicative of too many red cells which could be due to a number of conditions.


Haemoglobin A1c (HbA1c) is formed from glucose and haemoglobin. The amount of HbA1c is directly correlated to the amount of glucose in your bloodstream and provides an average picture of glucose levels over the last 2-3 months. It is therefore considered one of the best indicators for pre-diabetes and is also used by people with diabetes to keep their levels in control. If you are not a known diabetic and your levels are above the normal range, we always strongly recommend you see your GP.


HDL (high-density lipoprotein) works as a scavenger, picking up and carrying away excess cholesterol in your arteries and transporting it to the liver where it can be eliminated. It is therefore known as ‘good cholesterol’ with higher levels being a positive health benefit. In general people with high HDL are at lower risk of heart disease. Those with low HDL are at a higher risk. The best way to increase your HDL is through exercise.


C-reactive protein (crp) measures the amount of inflammation in your body. High levels are associated with an increased risk of developing cardiovascular disease and stroke. However, as CRP is a marker for general inflammation, it cannot identify the source of inflammation. Levels may also be raised due to a number of reasons including recent infections (especially bacterial), intense bursts of exercise or conditions such as arthritis. As CRP levels can fluctuate significantly, regular testing is recommended to establish a trend.


Iron is essential for the production of healthy red blood cells, specifically haemoglobin which transports oxygen around the body. Low levels of iron will result in fatigue and eventually lead to iron deficiency anaemia. There can be a number of reasons for iron deficiency including a poor diet or poor absorption, the latter of which can be caused by intensive exercise. The best source of iron is red meat, therefore people following a vegetarian or vegan diet can find it hard to absorb sufficient amounts.


LDL (low-density lipoprotein) is known as bad cholesterol because it can transport more cholesterol around the body than needed, leading to a build up on the walls of arteries. The higher the levels of LDL the higher the risk of developing heart disease. By lowering your LDL levels you can decrease the risk of cardiovascular disease. You can reduce your LDL by increasing the amount of unsaturated fat in your body by eating foods such as avocado or nuts & seeds.

Luteinising Hormone (LH)

Luteinising hormone (LH) plays a key role in the human reproductive system. In men, LH aids the production of testosterone to support sperm production, whilst in women, it plays a key role in ovulation. High or low levels of luteinising hormone are associated with problems with fertility and irregular periods. As women enter the menopause levels of LH will naturally rise, whilst levels in adult males tend to stay relatively constant throughout their lives.


Lymphocytes help protect the body against infection. They usually make up around 25% of the total white blood cell count. Low levels of lymphocytes can suggest a weakness in your immune system, whilst a high level can indicate infection (particularly viral) or increased level of inflammation. You can improve the efficiency of your immune system by staying hydrated and eating a good well balanced diet.

Magnesium (Serum)

Magnesium is an essential trace element and is important to maintaining good health. It performs a wide range of functions including maintenance of strong bones, keeping blood pressure normal, muscle contraction and energy production. Magnesium is supplied to the body through diet. Low magnesium in-take can affect calcium levels. Good sources of magnesium include vegetables such as broccoli and nuts.

Mean Cell Haemoglobin (MCH)

Mean cell haemoglobin (MCH) is a measurement of the amount of haemoglobin inside your red blood cells. High or low results can indicate different forms of anaemia leading to fatigue. This can be caused by nutritional deficiencies such as iron or B12. Above normal levels can also be a sign of dehydration.

Mean Corpuscular Haemoglobin Concentration (MCHC)

Mean corpuscular haemoglobin concentration (MCHC) measures the concentration of haemoglobin inside your red blood cells. MCHC, MCV and MCH all help to identify different forms of anaemia. Decreased MCHC values can be a sign of iron deficiency anaemia.

Mean Corpuscular Volume (MCV)

Mean corpuscular volume (MCV) indicates the average size of your red blood cells. High levels of MCV can sometimes be a sign of anaemia often caused by vitamin B12 or folic acid deficiency, whilst low levels are associated with iron deficiency. Both can lead to a reduction in energy and fatigue.

Mean Platelet Volume (MPV)

Mean platelet volume (MPV) is a measurement of the average size of blood platelets which play an important role in clotting. The higher the MPV the larger the average platelet size. The lower the number the smaller the average platelet size. Platelets that are more recently released from the bone marrow are usually larger in size. High MPV can be caused by iron or vitamin D deficiency.


Monocytes ingest bacteria and foreign particles in the blood which are harmful to the body. They usually make up around 5-10% of the total white blood cell count. An abnormally high level can be a sign of infection whilst low levels can mean that you have an increased susceptibility to infection. You can’t directly influence you monocyte count be you can improve the overall efficiency of your immune function through good nutrition.


Neutrophils help protect your body against infection and are the most abundant of white blood cell in the body. Neutrophils play an important role in the body’s inflammatory response and help to remove damaged cells and invading mico-organisms. Low levels of neutrophils can indicate a weakness in your immune system, whilst a high level can suggest infection (particularly bacterial) or increased inflammation.

Oestradiol (Oestrogen)

Oestradiol is the main form of oestrogen in women and levels will naturally reduce with age and decrease during the peri-menopausal stage, with a large decrease occurring at the start of menopause when the ovaries stop producing eggs. For example post-menopause women can expect their levels to fall below 100 IU/L. Low levels can cause mood swings, fatigue and a decrease in bone density leading to an increased risk of osteoporosis.

Omega 6: Omega 3 Ratio

Omega 6 and omega 3 are essential fatty acids are consumed through diet within a recommended ratio of 3:1. They are involved in a number of important functions including the regulation of blood pressure and inflammation, and therefore have an important role in protecting the body against heart disease. As Omega 6 is pro-inflammation while omega 3 is neutral, a diet which contains a lot of omega 6 and too little omega 3 will increase inflammation. Conversely, a diet with high levels of omega 3 and low levels of omega 6 will reduce inflammation.

Platelet Count

Your platelet count is the number of platelets in a given volume of blood. As platelets are important to the clotting of blood, low levels can increase the risk of abnormal bleeding.


Progesterone is produced by the body during ovulation and levels will change during the menstrual cycle. Progesterone levels in the blood start to rise when an egg is released from the ovary and then fall if the egg is not fertilised. If the test is taken at the correct time (day 21 for a 28 day cycle) a result >30 suggests ovulation has occurred, whilst levels <5 indicate that the ovary has failed to release an egg. Post-menopause levels will drop to below 0.401.


Prolactin is a hormone produced by the pituitary gland. Slight increases can occur as part of a stress reaction. However, if your level is consitently high this can cause supression of other pituitary hormones such as FSH and LH. High levels are expected during breast feeding as main role of prolactin is to produce milk.

RBC Distribution Width (RDW)

Red blood cells are the most common type of blood cell in circulation. RBC distribution width (RDW) is a measurement of the variation in the size of your red blood cells. Normal red blood cells are usually of a similar size. Some nutritional deficiencies e.g. iron, folate or vitamin B12 can cause a variation in red blood cell size leading to an increase in RDW.

Red Blood Cell (RBC)

Red blood cells are an important transporter of oxygen, taking it from the lungs to cells around the body. By keeping your RBC within the normal range you can ensure your body receives sufficient quantities of oxygen. Low RBC is often an indication of anaemia which can be due to a number or causes including nutrition deficiency e.g. low iron, folate or B12.

Sex Hormone Binding Globulin (SHBG)

SHBG is a protein which attaches itself to testosterone and controls how much of it is available to your body tissue. It is therefore useful in identifying testosterone deficiency in men and excess testosterone in women. High SHBG levels indicate less free testosterone is available to tissues which can lead to low libido in men and reductions in energy. Conversely, low SHGB levels indicate more total testosterone is available to the tissues which can lead in a condition known as Polycystic Ovary Syndrome in women.


Sodium is an electrolyte and plays a significant role in regulating water within the body as well as helping to regulate blood pressure. Too much sodium can cause high blood pressure in some cases, whilst too little sodium can lead to a decrease in blood pressure. After exercise, when the body has lost a lot of fluid, it is important to replace sodium through isotonic drinks or you can add a small amount of salt to squash.

Testosterone (total)

Testosterone plays an important role throughout the body, affecting the brain, bone and muscle mass, fat distribution, the vascular system, energy levels, sexual functioning and fertility. Testosterone in men is particularly beneficial in sports which require strength or power and can also help to support bone health and energy levels. However, excessively high levels can be a risk to health. Testosterone levels in men will naturally decline with age. High levels in women is associated with Polycystic Ovary Syndrome.

Thyroglobulin Antibodies

Thyroglobulin is a protein produced and used by the thyroid gland to make the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Elevated levels of thyroglobulin antibodies indicate that your thyroid gland is under attack from your immune system and this can affect the thyroid gland from working properly. Having raised antibodies can increase your risk of going on to develop a thyroid disorder and indicate an autoimmune condition.

Thyroid Peroxidase Antibodies

Thyroid Peroxidase (TPO) is an enzyme found in the thyroid gland which plays an important role in converting thyroxine (T4) to the biologically active triiodothyronine (T3). High levels of thyroid peroxidase antibodies indicate that your thyroid gland is under attack from your immune system. Raised levels increase your risk of developing a thyroid condition over time and are often found in those who have already been diagnosed with a thyroid disorder.

Thyroid Stimulating Hormone (TSH)

Thyroid Stimulated Hormone (TSH) plays an important role in regulating the production of hormones by the thyroid gland. High levels of TSH can indicate an underactive thyroid which can lead to fatigue and weight gain, whilst low levels are often associated with an overactive thyroid which can cause mood swings and difficulty in sleeping. Foods which contain the B vitamin group can play a large role in ensuring optimal thyroid function.

Thyroxine (T4, Free Direct)

A thyroxine (T4) test is used to check that the thyroid is performing properly. Thyroid hormones, such as thyroxine have a role to play in a wide range of the body’s functions including the maintenance of healthy bones and muscle control. An overactive thyroid can cause too much thyroxine to be released into the bloodstream, whilst an underactive thyroid can lead to too little thyroxine being produced. Both conditions can lead to weight gain and fatigue as well as our symptoms.

Total Cholesterol

Total cholesterol is a value made up of the different cholesterol components – HDL, LDL and triglycerides. High total cholesterol can indicate an increased risk of heart disease. However, having a high total cholesterol doesn’t always mean that you are at an increased risk of heart disease. It is therefore important to look at each individual component. For example, total cholesterol levels can be high due to a high level of HDL or good cholesterol which actually lowers the risk of heart disease.

Total Iron Binding Capacity (TIBC)

Total iron binding capacity (TIBC) results reflect the amount of iron in the body and should be viewed alongside iron and ferritin measurements. Typically TIBC levels will be high and iron levels low if you are iron deficient. Conversely, your TIBC level will be low and your iron level high if you have too much iron. It is important to maintain normal levels to prevent fatigue.

Total Protein

Total protein test is a measurement of albumin and globulin in the blood. The level of total protein in the blood is associated with liver and kidney function as well as nutritional status. As total protein alone cannot specifically identify a problem, results are interpreted alongside other liver function tests. High protein levels can sometimes be caused by dehydration.

Transferrin Saturation

Transferrin saturation is calculated using the results from iron and TIBC. Transferrin saturation is usually low in cases of iron deficiency and high if the body had too much iron. Too much or too little iron can have a range of negative health consequences including fatigue, headaches and weakness.


Triglyceride is the main form of fat found within our bodies. It is important for maintaining energy and provides the fuel for muscles to work. When you eat, excess calories which your body doesn’t need are converted into triglycerides. High levels can increase the risk of heart disease and pancreatitis. By lowering your triglycerides you can reduce the risk of heart disease. Triglyceride results can sometimes be raised if you’ve eaten before doing your blood test. If raised we recommend you repeat the test using a fasting blood sample i.e. first thing in the morning before food.

Triiodothyronine (T3, Free)

A Triiodothyronine (T3) test can indicate if the thyroid is performing properly. Triiodothyronine is the active form of Thyroxine (T4) and, as a thyroid hormone, plays an important role in many of the body’s functions including helping to regulate the body’s metabolism and muscle control. High levels of triiodothyronine may indicate an overactive thyroid the symptoms of which include fatigue, weight loss, irritability and irregular menstrual cycles. Low levels may indicate an underactive thyroid which can cause fatigue, weight gain and stiffness in muscles.


Both urea and creatinine are good indicators of whether the kidneys are working properly. Urea is a waste product which is formed in the liver when protein is metabolised. It is released by the liver into the bloodstream and carried to the kidneys where it is expelled within urine. If the kidneys are not performing correctly the level of urea in the blood will rise. Urea can also rise 2-3 days after intense exercise due to muscle breakdown and if your body is dehydrated.

Uric Acid

Uric acid or urate is a chemical compound which is produced when the body breaks down certain foods which contain purines. Most uric acid is removed from the body by the kidneys. Too much uric acid in the blood can lead to the formation of solid crystals in the joints – a condition known as gout, a form of inflammatory arthritis. High levels can also lead to the formation of kidney stones.

Vitamin A

Vitamin A is an essential nutrient and helps maintain normal vision particularly in dim light, the growth of healthy skin and bone development. Vitamin A also has an important role to play in helping the immune system fight infections. The body cannot make vitamin A, we are therefore reliant on dietary sources. The highest sources of vitamin A comes from liver, diary products, eggs and fish.

Vitamin D (25 OH)

Vitamin D plays an essential role in our health including the development and preservation of healthy bones, boosting our immune system, muscle function, energy levels and helping to reduce inflammation. Most of the body’s vitamin D is produced in the skin following exposure to sunlight, so people living in the UK are more prone to be deficient in this vital vitamin. Levels >75nmol/L are recommended for optimal health, or >90nmol/L for athletes. As it is difficult to increase levels of vitamin D through diet alone, supplements are usually required.

Vitamin E

Vitamin E is required for the proper functioning of many organs in the body. It has an important role to play in maintaining healthy skin, normal vision and the immune system. It also acts as an antioxidant which means it helps to slow down processes that can damage cells. Good sources of vitamin E include vegetable and rapeseed oil, eggs, cereals and seeds & nuts.

White Blood Cell Count (WBC)

White blood cell count (WBC) is a count of the actual number of white blood cells per volume of blood. Your white blood cells make up your immune system and help to protect the body against illness and disease. Low levels indicate a weakness in the immune system which can be associated with a number of conditions. Higher levels are common when your body is trying to fight off an illness or during extreme physical stress either through injury, emotional stress or excessive exercise.

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