Biomarker library
Biomarkers: what every value means
Biomarkers are the substances and cells the lab measures in your blood.
Per value you’ll read what it says about your body, when it runs too high or too low, and how to read it in context with your other values.
Measure your own values?Start today
112 biomarkers
Your red blood cells and platelets: how many there are, how big they are, how full they are and how many have just been added.
Erythrocytes
Erythrocytes are your red blood cells, and this value counts how many circulate per litre of blood. The count does not yet say how much oxygen your blood carries, that depends on how much haemoglobin sits in each cell; together with haemoglobin and the cell size it points at the kind of anaemia. Have blood drawn normally hydrated and not after hard exertion.
Hematocrit
Haematocrit is the share of your blood that consists of red blood cells: at 0.45 almost half your blood is cells and the rest plasma. It tells the same story as haemoglobin from another angle, and it is the value that gives away soonest whether your blood is thickened.
Hemoglobin
Haemoglobin is the protein in your red blood cells that carries oxygen from your lungs to your muscles and brain. The value says how much oxygen your blood can carry, and with that whether you have anaemia; why, ferritin and the cell size tell you. Have blood drawn well hydrated and not after hard exertion.
MCH
MCH is the average amount of haemoglobin per red blood cell: how well each cell is filled. It almost always moves with the cell size, low in iron deficiency and high in a deficiency of B12 or folate, and it is one of the first cell values to respond when you top up iron.
MCHC
MCHC is how densely the haemoglobin is packed in your red blood cells: the filling corrected for cell size. It is the slowest and most stable of the cell values, falls in an iron deficiency that has lasted a while, and a high value is more often a measurement artefact than a finding.
MCV
MCV is the average size of your red blood cells. It is the first fork in anaemia: small cells point at iron, large ones at B12, folate or alcohol, and because a red cell lasts four months, MCV is the report of the last few months, not of today.
Platelets
Platelets, or thrombocytes, are the smallest particles in your blood and the first to seal a wound. A low number most often comes from clumping in the tube, a virus or alcohol; a high number from an inflammation or iron deficiency.
RDW
RDW measures how much your red blood cells differ from each other in size. A low RDW is naturally low and healthy; a high RDW is an early signal that your bone marrow has started making cells of a different size, usually through iron deficiency or a deficiency of B12 or folate.
Reticulocytes
Reticulocytes are the red blood cells your bone marrow released in the last day or two. The count does not say how many red cells you have, but how hard your marrow is producing right now, and in anaemia that is exactly the question. Mind the unit: a count per litre and a per-mille are two different numbers.
Together the lipid profile, used to estimate cardiovascular risk.
ApoA1
ApoA1, apolipoprotein A1 in full, is the protein on the outside of your HDL particles, the particles that bring cholesterol back out of the vessel wall. Where HDL cholesterol weighs how much cholesterol those particles carry, ApoA1 counts the particles themselves. Higher is favourable, and exercise, losing weight and stopping smoking lift it.
ApoB
Apolipoprotein B, written as apoB on your results, is the structural protein sitting on every LDL, VLDL and Lp(a) particle, so that one measurement counts those particles rather than the cholesterol they carry. ApoB counts the particles that carry cholesterol into the artery wall and is therefore sharper than LDL with belly fat, insulin resistance and high triglycerides.
ApoB/ApoA1 ratio
The ApoB/ApoA1 ratio divides the number of particles that carry cholesterol into the vessel wall by the number of particles that take it back out: every depositing particle carries exactly one ApoB and every HDL particle ApoA1. A low ratio is favourable, and there is no agreed normal value to hold it against.
Atherogenic index of plasma
The atherogenic index of plasma, AIP for short, is the logarithm of your triglycerides divided by your HDL: the same two numbers as the triglyceride/HDL ratio, compressed onto a scale around zero. Below zero means your HDL is larger than your triglycerides, and that is the healthy picture. There is no agreed normal value, and the lower, the better.
HDL Cholesterol
HDL cholesterol, written as HDL-C on your results and known as the 'good' cholesterol, is the cholesterol carried back to the liver inside HDL particles. Read HDL beside LDL, triglycerides and non-HDL; in the risk estimate it counts through non-HDL, your total cholesterol minus your HDL.
LDL / HDL Ratio
The LDL/HDL ratio divides the cholesterol that enters your vessel wall by the cholesterol that leaves it again, and so sums up two sides of your lipid profile in one number. Lower is better, but the ratio does not say which of the two moved, and that is why you always read it beside LDL and HDL themselves.
LDL Cholesterol
LDL cholesterol, written as LDL-C on your results and known as the 'bad' cholesterol, is the cholesterol carried through your blood inside LDL particles that can build up in the artery wall. Read LDL beside non-HDL, HDL and triglycerides and as a trend; a markedly high value from a young age can be inherited, and then lifestyle is the foundation and medication usually joins it.
LDL/ApoB ratio
The LDL/ApoB ratio is your LDL cholesterol divided by your ApoB, both converted to mg/dl. Every LDL particle carries exactly one ApoB, so the ratio says how much cholesterol each particle holds: the lower it is, the smaller and denser your LDL particles, and those are the particles that most easily lodge in the vessel wall.
Lp(a)
Lipoprotein(a), written as Lp(a) on your results, is an LDL particle with an extra protein attached, and how much of it you have is set largely by your genes rather than by your lifestyle. Read your result beside the threshold in the same unit as your lab, and take a high Lp(a) as a reason to tackle LDL, blood pressure, weight and smoking more strictly.
Non-HDL Cholesterol
Non-HDL cholesterol is your total cholesterol minus your HDL: all the cholesterol carried by particles with an apoB protein on them, and those are the particles that build up in the artery wall. Work it out yourself if it is not on your results, total cholesterol minus HDL; it is the number your risk is estimated with.
NT-proBNP
NT-proBNP is a hormone fragment your heart muscle releases when the wall of your heart chambers is stretched more than usual. Below 125 pg/ml heart failure is unlikely, at every age; the value rises with the years and with a lower kidney function without your heart doing anything different.
TC/HDL ratio
The TC/HDL ratio divides your total cholesterol by your HDL, and so makes visible how your cholesterol is distributed: two people with the same total can have a quite different ratio. Below 5 is the target the one Dutch lab prints, and lower is better.
Total Cholesterol
Total cholesterol, written as TC on your results, is the sum of all the cholesterol in your blood: the LDL fraction, the HDL fraction and the cholesterol in the other lipoproteins. Read the total through its parts: LDL and non-HDL for your arteries, HDL and triglycerides for the pattern; the risk estimate uses total minus HDL.
Triglycerides
Triglycerides, written as TG on your results, are the fats in which your blood carries energy and your body stores it; they respond strongly to what you eat, to alcohol and to your metabolism. Read them beside HDL and LDL, and note whether you were fasting, because they run higher after a meal.
Triglycerides / HDL Ratio
The triglycerides/HDL ratio divides your triglycerides by your HDL, two numbers that move in opposite directions with belly fat and insulin resistance. The ratio is therefore a quick measure of the lipid pattern that goes with a deranged sugar metabolism, and it falls with losing weight, exercise and less sugar.
Liver values: the enzymes that leak under strain, plus what your liver makes and clears.
Albumin
Albumin is the most abundant protein in your blood, made by your liver. It keeps fluid in your blood vessels and carries calcium, hormones and medicines. The value says whether your liver is producing, whether you eat enough protein and whether you are inflamed, and it colours the results of calcium and zinc.
Albumin/globulin ratio
The albumin/globulin ratio divides the protein your liver makes by the protein mainly your immune system makes. The ratio is independent of how concentrated your blood was, and that is precisely what it exists for: a falling ratio points to an inflammation, a liver disease or protein loss.
ALP
ALP is an enzyme that enters your blood from two places: the bile ducts of your liver and the cells that build bone. So a high value is a bile drainage that falters or bones that are busy, and gamma-GT tells which of the two; with a vitamin D deficiency your bones work harder than you think.
ALT
ALT is an enzyme from your liver cells that leaks into your blood as soon as those cells come under strain. It is the most sensitive ordinary measure of your liver, and in anyone otherwise healthy a slightly raised value is almost always fatty liver: the condition you can fully reverse with lifestyle.
AST
AST is an enzyme that sits in your liver, but just as much in your muscles and your heart. It leaks into your blood when cells in one of those tissues break down, and so a high AST in anyone who does sport is more often a hard training session than a liver problem; the ratio with ALT tells which of the two.
AST / ALT Ratio
The AST/ALT ratio divides two liver enzymes that are distributed differently over the body, and so says where a rise comes from: below 1 is usually fatty liver, above 2 in a liver problem is usually alcohol. It only says something when one of the two is genuinely raised.
Bilirubin
Bilirubin is the yellow breakdown product of old red blood cells, which your liver makes soluble and drains through the bile. A slightly raised value with otherwise normal liver values is usually Gilbert's syndrome, a harmless variant that occurs in one in twenty people and protects rather than harms.
Conjugated bilirubin
Conjugated bilirubin is the part of your bilirubin your liver has already processed and made ready for removal through the bile. In a healthy adult it is virtually zero; if precisely this part rises, your liver has done its work and it is not getting away afterwards, and the question is about bile drainage.
FIB-4
FIB-4 is a calculation from four numbers you already have, your age, AST, ALT and platelets, that estimates how likely it is that your liver has scars. It is a sieve: a low score all but rules out advanced scarring, and in fatty liver that is exactly the question.
Gamma-GT
Gamma-GT is the enzyme of your liver and bile ducts that responds first to everything that quietly burdens the liver: alcohol above all, then belly fat, medicines and a bile drainage that falters. It often moves before ALT rises, and falls within weeks once you cut down.
Globulin
Globulin is everything in your blood protein that is not albumin: transport proteins, clotting proteins and above all the antibodies of your immune system. It is not measured but calculated, total protein minus albumin. How concentrated your blood is determines the number most often. The question is always which half of your total protein moved.
LDH
LDH is an enzyme that sits in almost all your cells and that is released as soon as cells break down somewhere: in your muscles after a hard training session, in your red blood cells with breakdown, in your liver with damage, or simply in the tube with a difficult draw. It is a broad alarm, not a pointer.
Total protein
Total protein adds up all the proteins in your blood: the albumin your liver makes and the globulins, which your antibodies belong to. The number itself says little; the distribution beside it, and how much fluid you had in your bloodstream, say everything.
Unconjugated bilirubin
Unconjugated bilirubin is the part of your bilirubin your liver has not yet processed: the pigment from old red blood cells, on its way to the liver. It is a subtraction, total minus conjugated, and it is the part that rises after a night of fasting and in Gilbert's syndrome, the harmless inborn variant in which the liver processes a little more slowly.
Kidney function: how well your kidneys filter your blood.
Creatinine
Creatinine is the waste product of your muscles that your kidneys filter out of your blood day and night, and the value is therefore the most common measure of how well your kidneys work. It also depends on how much muscle you have, and that makes reading it a matter of context. A value that stays the same over the years is what you want.
Cystatin C
Cystatin C is a small protein all your cells release at a steady rate and your kidneys filter out of your blood; because it does not come from muscle, it is a kidney value that does not distort with a lot or a little muscle mass. Read it beside creatinine: where the two diverge, the difference itself is the information.
eGFR
The eGFR is an estimate of how much blood your kidneys filter per minute, calculated from your creatinine, your age and your sex. It is the number your kidney function is read from, and above 60 it is healthy; the trend over the years says more than one value.
eGFR from cystatin C
This eGFR estimates your kidney filtration from cystatin C instead of from creatinine: a protein all your cells make and that does not depend on your muscle mass. It is the second reading beside your ordinary eGFR, and the difference between the two is the information.
Urea
Urea is the waste product your liver makes when protein is broken down and which your kidneys filter out of your blood; it moves with what you eat and drink, and therefore says less about your kidneys than creatinine. Read it beside creatinine and eGFR: if those are normal, it is fluid and food, not your kidneys.
Uric acid
Uric acid is the end product of the breakdown of purines, building blocks from your own cells and from your food; your kidneys are its main exit, and too much of it can form crystals in a joint. That is gout, but one high value is not yet gout; read it beside your kidney function, triglycerides and blood sugar, and change what you drink first.
Sex hormones, the pituitary signals that drive them, your stress hormone and your endocrine reserve. With these values the moment of the draw shapes the result.
Cortisol
Cortisol is the hormone your adrenal glands use to wake your body up and put it on alert: it frees energy, keeps your blood pressure up and dampens inflammation. It follows the clock, high in the morning and low in the evening, and that is why a cortisol value says nothing without the time of the draw.
DHEA-S
DHEA-S is the storage form of DHEA, the hormone your adrenal glands make as raw material for testosterone and oestrogen. It peaks around your twenties and falls steadily after that, and because it does not move with the clock, it is the calm counterpart of cortisol from the same glands.
FAI (free androgen index)
The free androgen index is a calculation: your total testosterone divided by your SHBG, the protein that binds testosterone. The result estimates how much of your testosterone is free and therefore works, and is above all in women with excess hair growth, acne or an irregular cycle a more usable number than the total alone.
Free testosterone
Free testosterone is the part of your testosterone not bound to protein and therefore able to do its work, calculated from your total testosterone, your SHBG and your albumin. It is the number that fits complaints best when SHBG is abnormal.
FSH
FSH, in full follicle-stimulating hormone, is the signal with which your brain sets the ovaries or the testes to work: low when they respond well, high when they respond less, and permanently high after the menopause. In women not one normal value but a range per cycle phase.
IGF-1
IGF-1 is the substance through which your growth hormone does its work: your liver makes it as soon as growth hormone is released, and it sits stably enough in your blood to measure. The value falls with age, drops when you eat too little and rises with too much growth hormone. Read the SD value rather than the concentration.
LH
LH, in full luteinising hormone, is the hormone from your pituitary that in women gives the starting signal for ovulation and in men sets the testes to making testosterone. In women not one normal value but a range per cycle phase, with a surge around ovulation a multiple higher than the rest.
Oestradiol
Oestradiol is the main oestrogen: in women the hormone that carries the first half of the cycle and keeps bone, vessels and mucous membranes healthy, in men a small amount that arises from testosterone. A regular cycle with ovulation is the health signal, and eating too little, training too much and stress are what switch it off.
Progesterone
Progesterone is the hormone of the second half of your cycle, made by the corpus luteum left behind after ovulation; it only rises if ovulation has happened, and that is exactly what it measures.
Prolactin
Prolactin is the hormone from your pituitary that starts milk production after childbirth and outside that time acts as a brake on your sex hormones: a raised value suppresses LH and FSH, and with them the cycle, desire and testosterone. Have blood drawn in the morning, rested and without exercise or sex beforehand, and read it beside LH, FSH and TSH.
SHBG
SHBG, in full sex hormone binding globulin, is the protein from your liver that holds testosterone and oestradiol in your blood and so decides how much of them stays active. It is also one of the first values to give away insulin resistance. Read it beside total testosterone and have the free share calculated.
Total testosterone
Total testosterone adds up all the testosterone in your blood, the part bound to protein and the free part together. It is the hormone that carries muscle, bone, desire and energy, and one of the hormones that move most with how you live. Have blood drawn before ten in the morning, and read it beside SHBG, which decides how much of it works.
Whether your thyroid runs fast or slow, and what drives it.
Free T3
Free T3 is the active thyroid hormone, the part that travels loose in your blood and drives your metabolism. It falls first with illness, crash diets and eating too little, and that is usually not a thyroid problem but your body saving energy.
Free T4
Free T4 is the thyroid hormone circulating freely in your blood right now, not bound to protein, and therefore the part that actually reaches your cells. It says what your thyroid delivers, where TSH says what your brain asks; together they tell whether your thyroid is underactive, overactive or in balance.
Tg antibodies
Tg antibodies are antibodies against thyroglobulin, the protein your thyroid stores its hormone in. They arise in the same autoimmune process as TPO antibodies and rarely add anything to them; their own role lies in the follow-up after thyroid cancer.
TPO antibodies
TPO antibodies are antibodies your immune system makes against the enzyme your thyroid uses to make hormone. They explain why a thyroid is becoming underactive, while TSH and free T4 show that it is; with a normal TSH they say something about the chance of later, not about now.
TSH
TSH is the hormone your brain uses to steer your thyroid, and it works like a thermostat: if the thyroid delivers too little, TSH rises, if it delivers too much, TSH falls. That makes TSH the most sensitive value to see whether your thyroid is in balance, long before the thyroid hormones themselves deviate.
Your blood sugar now, and on average over recent months.
C-peptide
C-peptide, on a request also listed as insulin connecting peptide, is the piece of protein cut out when insulin is made and released in equal amounts with insulin. It therefore counts how much insulin your pancreas makes itself, even if you inject insulin. It matters most once blood sugar is no longer normal, to tell an overworking pancreas from an exhausted one.
eAG (estimated average glucose)
The eAG is your HbA1c converted to the average blood sugar of the past two to three months, in the same mmol/L as a glucose meter. It is not a separate measurement but a translation, and it says exactly what your HbA1c already said, in a number you know from your meter.
Fasting glucose
Fasting glucose, on your results also written as fasting blood sugar or fasting plasma glucose, is the amount of sugar in your blood after a night without eating: the level your body falls back to once your last meal has long been processed. The value moves late, so the direction within the range says more than one number.
HbA1c
HbA1c, in full haemoglobin A1c and on your results also glycated haemoglobin or GlyHb, is the share of your haemoglobin that glucose has attached itself to, and so the average of your blood sugar over the past two to three months. Read it as a trend beside fasting glucose, triglycerides and HDL; lifestyle shows up in it only after months.
Insulin
Insulin is the hormone your pancreas uses to move glucose out of your blood and into your cells. A fasting insulin shows how much effort your body puts in to keep your blood sugar normal, and that number moves years before the blood sugar itself does. Have blood drawn fasting, and read the value beside your fasting glucose, triglycerides and HDL.
TyG index
The TyG index is a calculation from your fasting triglycerides and your fasting glucose, meant as an estimate of insulin resistance without insulin having to be measured. Both numbers are on virtually every report. Lower is favourable; above about 4.68 the index fits a body that responds less well to insulin.
Iron status: your store, its transport, and how much is occupied.
Ferritin
Ferritin is the protein your body stores iron in, and the value in your blood is the measure of how large that store is. It is the first value to know when you are tired, because the store runs empty long before you have anaemia.
Serum Iron
Serum iron is the iron currently on its way through your blood, bound to its transport protein. It is a snapshot that sits highest in the morning and shoots up after an iron tablet or a piece of meat; on its own it says little, as the building block of transferrin saturation a lot.
Transferrin
Transferrin is the protein that carries iron through your blood, the taxi between gut, store and bone marrow. Your liver makes more of it when iron is scarce and less with inflammation, so a high transferrin is a body looking for iron and a low transferrin usually a body that is inflamed or undernourished.
Transferrin Saturation
Transferrin saturation is the share of your iron transport that is occupied right now: how many of the taxis have a passenger. It is the best measure of how much iron your cells can take now, low in a deficiency, high in overload, and the value that shows a deficiency that ferritin hides in inflammation.
The B vitamins that can be measured in blood, and the by-products that sometimes reveal a shortfall before the vitamin itself does.
Folate
Folate, or folic acid, is the B vitamin from green vegetables and legumes that your cells need to make DNA and divide. Too few vegetables, alcohol and a pregnancy are the most common reasons for a deficiency, and supplements the most common for a high value.
Homocysteine
Homocysteine is an intermediate of your protein metabolism that your body clears with folate, vitamin B12 and B6. If it rises, one of those three is falling short, or your kidneys are clearing it less well; it is a measure of your B vitamins, not of your heart.
MMA
Methylmalonic acid, or MMA, is an intermediate of your metabolism that is left behind when your cells can use too little vitamin B12. It measures the consequence of a deficiency instead of the store, and so sees through a normal-looking B12. A reduced kidney function lifts it without a deficiency. A low value has no meaning.
Vitamin B1
Vitamin B1, thiamine, is the vitamin your cells use to turn carbohydrates into energy. Your body holds only a few weeks' supply of it, so the value mostly reflects what you took in recently, and alcohol.
Vitamin B12
You need vitamin B12 for your nerves, your DNA and making red blood cells. It comes almost only from animal food and has a complicated uptake, so a deficiency comes as often from the stomach as from the plate.
Vitamin B6
Vitamin B6 is the helper of more than a hundred enzymes, from your protein metabolism to making serotonin and dopamine. It is the one B vitamin where too much is a problem too: long-term high-dose supplements damage the nerves.
Minerals and trace elements, the vitamin that regulates their uptake, and the fatty acids in your cell walls.
Calcium
Calcium is the mineral of your bones, and the small part in your blood lets your nerves fire, your muscles contract and your blood clot. Your body holds that part within a narrow band, with PTH and vitamin D as regulators; a high value you take seriously, a low one is usually a matter of protein or vitamin D.
Ceruloplasmin
Ceruloplasmin is the protein your liver makes to carry copper through your blood, and it is at the same time an inflammation protein. Without this value a copper value cannot be read; together they show whether a change is about copper or about its transport. A low value is the side to take seriously, a high one is usually inflammation or the pill.
Copper
Copper is a trace element in the enzymes that make iron usable, keep connective tissue firm and protect your nerves. It travels through your blood bound to ceruloplasmin, so the value moves as much with that protein as with your copper itself. So read it beside ceruloplasmin, and beyond that beside zinc, CRP and your blood count.
Corrected Calcium
Corrected calcium is a calculation, not a measurement: your total calcium adjusted for your albumin, because half the calcium is bound to that protein. It is the more honest measure when your albumin is low, and unnecessary when your albumin is normal.
Magnesium
Magnesium is the mineral that keeps hundreds of enzymes in your cells at work, from your energy metabolism to your muscles and your heart rhythm. Only one percent of it is in your blood, so the blood value is a coarse measure; a low value is almost always loss through medicines or alcohol.
Omega-3 index
The omega-3 index is the share of EPA and DHA, the two omega-3 fatty acids from oily fish, in the wall of your red blood cells. Because those cells last for months, the index shows what you took in from oily fish or fish oil over the past months. Read it against your own previous value at the same lab; there is no Dutch band.
Selenium
Selenium is a trace element that sits in the enzymes that neutralise harmful by-products of your metabolism and that convert thyroid hormone into its active form. How much you take in depends on the soil your food grew on, and a few Brazil nuts a week is enough. Look at the unit on your results before the number, because µg/L and µmol/L are two scales.
Vitamin D
Vitamin D is the hormone your skin makes from sunlight and that lets your gut absorb calcium for your bones and muscles. The blood value is your store of the past weeks, and in the Netherlands it is too low in most people from October to April, unless you top up.
Zinc
Zinc is the trace element behind hundreds of enzymes, your immune system, your wound healing, your sense of taste and the making of testosterone. Your body holds no store of it, so the supply counts every week, and the value in your blood moves with albumin and with inflammation.
How active your defences are, what kind of reaction it is, and which antibodies you have made.
ANA (antinuclear antibodies)
ANA are antibodies your immune system makes against parts of your own cell nuclei. The result is a word, negative or positive, sometimes with a titre. Negative is the usual result; a positive ANA occurs in about one in eight healthy people, more often with age, and is not a diagnosis in itself but the first step in the work-up of an autoimmune disease.
Anti-CCP
Anti-CCP, in full antibodies against cyclic citrullinated peptides, is the antibody most specific to rheumatoid arthritis and one that can precede it by years. It is a test for joint complaints, not a screening test. Positive fits rheumatoid arthritis strongly, even years before the complaints, and smoking is the biggest lifestyle factor behind it.
Basophils
Basophils are the rarest white blood cells, filled with histamine, and they take part in allergy and in inflammation that has been running a while. A low count is never a finding; a rise is usually mild and says something only in the pattern with the other white cells. Only a count that persistently sits far above the band is taken seriously.
CRP
CRP is the protein your liver makes within hours as soon as there is inflammation somewhere in your body, and it is the fastest and broadest gauge of it. It says that something is going on, not where or why, and a low value is the healthy state.
Eosinophils
Eosinophils are the white blood cells of allergy and parasites. The count rises with hay fever, asthma, eczema, a reaction to a medicine or a worm infection, and it falls towards zero through cortisol and prednisone. It is the upper end that means something, and in the pollen season the count naturally sits higher in anyone with hay fever.
ESR (sedimentation rate)
The sedimentation rate measures how fast your red blood cells sink to the bottom of a tube in an hour. With inflammation your liver makes proteins that make the cells stick together, and clumps sink faster; so a simple measurement becomes a slow but broad gauge of inflammation. Read it beside CRP: it moves over days to weeks, where CRP responds within a day.
IgA
IgA, in full immunoglobulin A, is the antibody of your mucous membranes: the first layer of defence in your gut, airways, saliva and tears. This test adds up all your IgA in the blood, and matters above all with a coeliac test and with recurring infections.
IgG
IgG is the largest group of antibodies in your blood: the proteins your immune system makes after it has come to know a pathogen, and which often remain for years afterwards. Total IgG shows whether your immune system can make enough antibodies. Read IgG beside IgA and IgM, because the three together draw the pattern, and beside CRP and ESR.
IgM
IgM, in full immunoglobulin M, is the antibody your immune system makes first when it meets something new: large, coarse and fast, and gone again after a few weeks once IgG takes over. This test adds up all your IgM in the blood.
Leukocytes
Leukocytes are your white blood cells, the army of your immune system, and the total count says how large that army is in your blood right now. It rises with a bacterial infection, stress and smoking, and falls with a virus or through medicines. The count says that something is going on, and the differential says what.
Lymphocytes
Lymphocytes are the white blood cells that recognise viruses, make antibodies and remember what they have seen. The count rises with a viral infection and in the recovery phase after it, and falls through cortisol: with stress, acute illness and prednisone. Always read it beside the neutrophils, because together they say whether it is a virus or a bacterium.
Monocytes
Monocytes are the cleaners of your immune system: white blood cells that move into the tissue, become macrophages there and digest dead cells, bacteria and debris. The count rises in the recovery phase after an infection and with inflammation that has been running a while.
Neutrophils
Neutrophils are the largest group of white blood cells and the first on the scene at a bacterium or a wound. The count rises with a bacterial infection, stress, exercise and smoking, and falls after a virus or through medicines. Read the absolute count, not the percentage, and always beside lymphocytes and CRP.
NLR (neutrophil/lymphocyte)
The NLR is your neutrophil count divided by your lymphocyte count, two numbers already in your blood count. The ratio shows where the balance lies between the stress response of your immune system and recovery, and it rises with infection, inflammation, lack of sleep and overtraining.
PLR (platelet/lymphocyte)
The PLR is your platelet count divided by your lymphocyte count, two numbers already in your blood count. Platelets rise over days to weeks with inflammation and lymphocytes fall with stress, so the ratio shows whether your body has been loaded for a while.
Rheumatoid factor
Rheumatoid factor is an antibody directed against part of your own antibodies. It is the oldest blood test for joint complaints: sensitive to rheumatoid arthritis, but also positive with infections, other autoimmune diseases and some healthy older people. Positive fits rheumatoid arthritis when there are joint complaints, and without complaints is usually age, smoking or a past infection.
SII (inflammation index)
The SII, in full the systemic immune-inflammation index, is your platelet count times your neutrophil count, divided by your lymphocyte count, three numbers already in your blood count. The index bundles the fast stress response of your immune system, the slower inflammatory response of your platelets and recovery into one number, and it rises with infection, inflammation, lack of sleep and hard training.
tTG-IgA
tTG-IgA, in full IgA antibodies against tissue transglutaminase, is the blood test that starts an investigation for coeliac disease. It is only reliable if you eat gluten and your total IgA is normal, and those two things decide how you read it.
The salts behind fluid balance, nerve signals and heart rhythm.
Bicarbonate
Bicarbonate is the main buffer with which your blood keeps its acidity within a very narrow margin. Your lungs and your kidneys regulate it together, and the value shows whether that buffer is under pressure. Have a low value measured again first with a closed tube, and read it beside chloride, sodium, potassium and your kidney function.
Chloride
Chloride is the other half of table salt, the negatively charged particle that follows sodium everywhere and together with bicarbonate keeps the acidity of your blood in balance. The value rarely says anything on its own; it gains meaning beside sodium, potassium and bicarbonate.
Ionised calcium
Ionised calcium is the free part of the calcium in your blood: the part not bound to protein and therefore actually working in your nerves, muscles and clotting. It is the value your body itself guards, and the measurement that bypasses a deviating albumin instead of correcting for it.
Phosphate
Phosphate is the mineral that builds your bones together with calcium and passes energy on in every cell. Your kidneys, PTH and vitamin D together regulate how much stays in your blood, and the value is above all a kidney value. Read it beside calcium, PTH, vitamin D and your kidney function: first the kidneys, then calcium, then PTH.
Potassium
Potassium is the mineral your nerves fire with and your muscles contract with, your heart first of all. Almost all of it sits inside your cells, and the small part in your blood is held within a narrow band by your kidneys; too low usually comes from loss, too high often from the draw itself.
PTH (parathyroid hormone)
PTH is the hormone of your parathyroid glands that keeps your calcium in place from minute to minute: if calcium falls, PTH rises and pulls calcium from bone, kidneys and gut. The value does not say how much calcium you have, but how hard your body works to keep it in place.
Sodium
Sodium is the salt in your blood, and the value is not about how much salt you eat but about how much water you hold on to. Your brain and kidneys keep it within a band of less than ten units, because your brain cells swell or shrink with every shift.
Usually measured for urinary symptoms or from middle age onward.
Why do normal ranges differ between laboratories?
The Netherlands has no national reference table for blood values. Every laboratory publishes its own normal ranges, based on its own equipment, its own method and its own reference population, so the same result can be flagged at one lab and not at another. That is why every page in this library shows what four major Dutch laboratories publish themselves, and where those ranges overlap and differ.
Frequently asked questions
Biomarkers are the substances and cells a laboratory measures in your blood: enzymes, hormones, vitamins, fats and cells. Together they show how your organs are doing, how your body handles fuel and whether there is inflammation. One value rarely tells the story; the picture emerges from several read side by side.
Take control now.
Membership · most popular
€1/day
Core measures the values on this page, together with the rest of the panel.
- Annual blood test (60 values)
- Your biological age
- Personal action plan
- Personal AI coach
- Wearable integration
- 10% cashback in credits
Start your membership
No referral needed · Results < 24 hours
Rather start differently? Biological age (€69)