Home › Biomarkers › Calcium
In one study, 24.5% of 200 blood samples taken for a liver test had a low calcium level.[1]
On this page you can read what calcium is, what the guidelines say about a value that is too low or too high, what affects your level and which values are best to look at alongside it.
Also known as: kalk, serum calcium, total calcium. At the lab: CA.
Calcium (in Dutch also called kalk) is a mineral. It is found mainly in dairy, such as milk and cheese, and in dairy alternatives with added calcium. You also find it in grain products such as wholemeal bread and in green vegetables such as kale and spinach.[2]
In dairy, calcium comes mainly in the form of calcium phosphate. Your body absorbs this form well. Vitamin D helps your gut absorb calcium well and is needed to lay calcium down in your bones.[2]
One study found that calcium in the blood is closely linked to albumin. The link with the total amount of protein in the blood was weaker.[1]
Calcium has several jobs in your body. It matters for your bones and teeth. It helps your nerves and muscles work properly. It plays a role in blood clotting. And it helps carry other minerals, such as sodium, potassium and magnesium, through your cells.[2]
Too little calcium is a risk for women from the age of 50 and for men from the age of 70. At that age, the body absorbs calcium into the blood less well. The bones slowly lose calcium, which is why older people break a bone more often. Exercise helps counter the loss of calcium from the bones later in life.[2]
If children get less than 125 milligrams of calcium a day, bone formation may be incomplete. The skeleton can then become deformed and muscle cramps can develop. This is often caused by too little vitamin D, even when there is enough calcium in the diet.[2]
Labplusarts, the lab BioProfile works with, uses a reference value for calcium of 2.15 to 2.55 mmol/l. The lab calls a value between those limits normal.[3]
| Value | What the lab says | Who it is for |
|---|---|---|
| 2.15 to 2.55 mmol/l[3] | Normal according to the lab | Blood that Labplusarts tests for calcium |
Source: Labplusarts reference value for calcium (CA), for blood tested by this lab.[3]
Calcium in your blood is closely linked to albumin. In one study, the lab adjusted the calcium values for albumin. After that, the values fell within that lab's normal range. So a low value can also point to low albumin in your blood, not just to low calcium.[1]
In the same study, 3% of the samples had a raised calcium level. In 39 samples with high levels of certain proteins in the blood, adjusting for albumin gave a normal calcium level. So a high value can also be linked to the proteins in your blood.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Vitamin D makes sure your gut absorbs calcium well. If you have too little vitamin D, your body may not absorb calcium from your food properly, even when your diet contains enough calcium.[2]
Oxalic acid, from vegetables such as rhubarb and spinach, reduces calcium absorption. Phytic acid from grains also works against that absorption. Salt, alcohol and caffeine, found in coffee, tea and cola among others, make you lose a little more calcium through your urine.[2]
EFSA sets an upper limit for adults of 2.5 grams of calcium a day, from food and supplements combined. Too much calcium can lead to calcification of your kidneys and of the walls of your blood vessels. This applies especially with long-term use of antacid tablets containing calcium bicarbonate.[2]
The calcium level in your blood moves with albumin. That is why a lab can adjust the calcium level for albumin. In one study, this adjustment worked better than an adjustment based on the total amount of protein.[1]
Calcium is included in BioProfile 77, 87, 121 and 150.[4]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
