Blood values explained

Testosterone is the primary male sex hormone and plays a role in muscle mass, energy, libido, and mood. A test gives insight into your level, with personal explanation from our doctors.

Cortisol is a hormone that plays a role in stress, energy, and metabolism, among other things. A morning measurement gives insight into your cortisol level, with personal explanation from our doctors.

DHEA-S is an adrenal hormone that serves as a precursor for the sex hormones. The level declines gradually with age and gives insight into the androgen production of the adrenal gland.

FSH is a hormone from the pituitary gland that drives the maturation of the follicles in women and plays a role in sperm production in men. With personal explanation from our doctors.

LH is a hormone from the pituitary gland that drives the sex glands. In men LH stimulates testosterone production, in women LH peaks around ovulation. With personal explanation from our doctors.

Oestradiol (E2) is the most important oestrogen and plays a role in the menstrual cycle, the bones, and the menopause. In women the level fluctuates considerably across the cycle, so the moment of testing partly determines the result.

Progesterone is formed after ovulation and prepares the womb lining. The level depends strongly on the point in the cycle, which is why testing usually takes place during the second half of the cycle.

Prolactin is a hormone from the pituitary gland, known for breastfeeding, but present in men as well. An elevated level can affect the cycle or libido, and is often temporary in nature.

SHBG is the transport protein that binds sex hormones in your blood. The level of SHBG helps determine how much testosterone remains freely available, with personal explanation from our doctors.

Free testosterone is the portion of your testosterone that is not bound to protein and is therefore biologically available. This measurement helps to interpret your total testosterone level, with personal explanation from our doctors.

TSH is the hormone from the pituitary gland that signals the thyroid, and the usual first step in thyroid testing. A measurement gives insight into how strongly your body is stimulating the thyroid.

Anti-TPO are antibodies against the thyroid enzyme thyroid peroxidase. Their presence fits with an autoimmune thyroid condition such as Hashimoto's, and gives context to an abnormal thyroid result.

Free T3 is the most active thyroid hormone, largely formed from T4 in the tissues. A test adds to TSH and Free T4 and gives insight into the hormone that does the work inside the cells.

Free T4 is the thyroid hormone thyroxine that circulates in your blood unbound to protein, and is therefore available to the tissues. A test gives insight into what your thyroid itself produces.

Vitamin D plays a role in bone strength, muscle function and the immune system. A measurement provides insight into your 25-OH vitamin D level, with personal explanation by our doctors.

Vitamin B12 (cobalamin) plays a role in the production of red blood cells and the functioning of the nervous system. A test gives insight into your B12 level, with personal explanation from our doctors.

Folic acid (vitamin B11 in the Netherlands, B9 internationally) is essential for cell growth, DNA production, and blood formation. A test gives insight into your folate status, with personal explanation from our doctors.

Vitamin A is a fat-soluble vitamin with a role in vision, the skin, and the immune system. Because the body stores vitamin A, the level can also become too high with excessive supplementation.

Vitamin B1 (thiamine) is needed for energy metabolism and nerve function. A test gives insight into your vitamin B1 level in the blood.

Vitamin B6 (pyridoxine) plays a role in protein metabolism, the nervous system, and the production of neurotransmitters. With this vitamin the level can also be too high, for example with long-term supplementation.

Magnesium is a mineral that plays a role in more than 300 enzymatic processes, including muscle and nerve function. A test gives insight into the magnesium level in your blood.

Calcium is a mineral that plays a role in building bone, in muscle contraction and in the conduction of nerve signals. A test gives insight into the calcium level in your blood.

Zinc is a mineral with a role in immune defence, wound healing, the skin, and taste. A serum zinc measurement gives insight into the zinc level in your blood.

Ferritin reflects the amount of iron stored in the body. A test gives insight into your iron stores, with personal explanation from our doctors.

Serum iron is the amount of iron circulating in your blood at the moment of the blood draw. A test gives insight into that circulating iron, as part of the broader picture of your iron status.

Transferrin is the protein that carries iron through your blood. The value says something about your body's demand for iron and, together with ferritin and serum iron, forms the picture of your iron status.

Total cholesterol is the sum of all the cholesterol carried in your blood. This single measurement gives a first impression of your cholesterol level, with personal explanation from our doctors. For the complete picture, HDL, LDL, and triglycerides belong alongside it.

Homocysteine is an amino acid whose elevated level is associated with cardiovascular risk factors and B vitamin status. A test provides insight, with personal explanation from our doctors.

HDL cholesterol carries excess cholesterol back to the liver, which is why it is often called "good cholesterol". A test provides insight into your HDL level, with personal explanation from our doctors.

LDL cholesterol is the cholesterol that can settle in the artery wall, which gives it a central role in the risk of cardiovascular disease. A test provides insight into your LDL level, with personal explanation from our doctors.

Triglycerides are the fats the body stores as energy. The level is strongly influenced by your last meal and by alcohol, and is linked to lifestyle, weight, and blood sugar regulation.

ApoB counts how many cholesterol particles are travelling through your blood that can lodge in the artery wall. LDL measures how much cholesterol sits inside those particles. This single measurement brings that number into view, with personal explanation from our doctors.

Lipoprotein(a) is a largely inherited lipid particle that plays a role in cardiovascular risk alongside your cholesterol. The level is essentially fixed in your genes, so a single measurement usually answers the question for years. Including personal explanation from our doctors.

HbA1c gives a picture of your average blood sugar over the past 2–3 months. A test provides insight into your blood sugar regulation, with personal explanation from our doctors.

Glucose is your blood sugar level at the moment of the blood draw. You choose whether to come in fasting or not. Fasting is the usual way to assess blood sugar regulation; non-fasting is a snapshot that is easier to fit into your day.

Insulin is the hormone from the pancreas that lowers blood sugar. Measured while fasting, it gives additional insight alongside glucose and HbA1c, for example with questions about sensitivity to insulin. Fasting is required.

ALT and AST are enzymes found mainly in the liver cells. When they are released into the blood, that gives insight into irritation or damage to liver cells.

Bilirubin is a breakdown product of red blood cells that is processed by the liver and leaves the body through bile. A test gives insight into how your liver processes bilirubin.

Gamma-GT is an enzyme that points mainly towards the bile ducts and responds sensitively to alcohol and certain medicines. It is often the first liver value to change.

Alkaline phosphatase is an enzyme with bone and liver as its main sources. The value gives insight into bile drainage and bone metabolism, with personal explanation from our doctors.

Creatinine and eGFR together give insight into the filtration function of your kidneys. The eGFR is calculated based on your creatinine level, among other factors.

Cystatin C estimates the filtration function of your kidneys, independent of your muscle mass. It is a valuable addition or alternative when creatinine is difficult to interpret.

Potassium is an electrolyte found mainly inside the cells that plays a role in the signal conduction of muscles and the heart. A test gives insight into the potassium level in your blood.

Sodium is the most important electrolyte outside the cells and helps determine the fluid balance. A test gives insight into the water and salt balance in your blood.

Urea is a waste product of protein metabolism that is excreted by the kidneys. A test gives insight into the urea level in your blood, as part of the picture of your kidney function and fluid balance.

Uric acid is a waste product formed when purines are broken down and leaves the body via the kidneys. The value is known from gout and is also linked to lifestyle and to the way your kidneys work.

CRP (C-reactive protein) is the most widely used marker for detecting inflammation in the body. A test gives insight into your current inflammatory status, with personal explanation from our doctors.

The erythrocyte sedimentation rate (ESR) shows how quickly red blood cells settle in one hour. It is a classic, broad inflammation marker that responds slowly and therefore shows something different from CRP.

Rheumatoid factor is an antibody the immune system can produce against the body's own protein. The test is used for questions about joint complaints and is emphatically one piece of the puzzle, not a diagnosis in itself.

PSA (Prostate-Specific Antigen) is a protein produced by the prostate. The level provides information about the prostate and is often measured as part of prostate monitoring.

Selenium is a trace element with a role in the thyroid, immune defence and the protection of cells against damage. A measurement gives insight into the amount of selenium in your blood.

Beta-HCG (human chorionic gonadotropin) is the hormone produced during pregnancy. A blood test detects this hormone early and is used to confirm a pregnancy and follow its first weeks.

Haemoglobin is the protein in your red blood cells that carries oxygen around the body. A test gives insight into your haemoglobin level, the value that is looked at when the question is whether there is anaemia.