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Platelets, also called thrombocytes, are small blood cells that your blood needs in order to clot. A value lower than normal can point to a blood disorder or to inflammation of or damage to the bone marrow; a value higher than normal can point to anaemia, inflammation of the bowel or heavy blood loss.[1]
On this page you can read what platelets are, what the guidelines say about a value that is too low or too high, what affects your value and which values are best to look at alongside it.
Also known as: thrombocytes, platelet count, PLT. At the lab: KBB.
Platelets, also called thrombocytes, are small blood cells. They are made in your bone marrow, the spongy tissue inside your bones. You need them for your blood to clot.[1]
A clot is a mass of blood that forms when platelets, proteins and cells in your blood stick together. If you get a wound, your body makes a clot to stop the bleeding.[1]
There are two kinds of platelet test. A count measures the number of platelets in your blood; function tests look at how well your platelets can form a clot. For the test, a healthcare provider takes blood from a blood vessel in your arm with a small needle, and this usually takes less than five minutes.[1]
A platelet count is mainly used to follow how a value develops during care, and to detect conditions in which you bleed too much or your blood clots too much. The count is often part of the full blood count, a test that is often done during a routine check-up.[1]
With a value that is lower than normal, MedlinePlus mentions, among other things, bleeding for a long time after a small cut or a wound, nosebleeds, bruises with no clear cause, tiny red dots on the skin, purple, red or brown patches on the skin, heavy or long periods, and blood in your urine or stools.[1]
With a value that is higher than normal, MedlinePlus mentions numbness in your hands and feet, headache, dizziness, weakness, and pain, swelling and warmth in your lower legs. Function tests look at how well your platelets can form a clot, for example before a complex operation with a higher chance of bleeding, or if you or your family have a history of bleeding problems.[1]
The laboratory BioProfile works with, Labplusarts, uses a reference value of 150 to 400 10^9/l for the platelet test (KBB). The lab calls a value between these limits normal.[3]
| Value | What it can mean | Who it is for |
|---|---|---|
| 150 to 400 10^9/l[3] | The lab calls a value between these limits normal | The platelet test (KBB) at Labplusarts |
Reference value from Labplusarts, the laboratory BioProfile works with, for the platelet test (KBB); list dated 24 September 2026.[3]
MedlinePlus writes that a value lower than normal can point to a blood disorder, an illness caused by a virus, a condition in which your body attacks its own healthy tissue, inflammation of or damage to the bone marrow, a liver condition or too little vitamin B12. A mildly low value that can occur when you are pregnant is also on that list. An international working group of experienced doctors also set out which terms, definitions and grades of severity are used for a low value in adults and children.[1, 2]
MedlinePlus writes that a value that is higher than normal can point to a condition of the lungs or the chest, anaemia, an inflammation of the bowel, an inflammation of the joints, an illness caused by a virus or a bacterium, or heavy blood loss. With a higher value, your blood can clot more than it needs to, and a clot can block the flow of 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.
A platelet count is also used to monitor people who take medicines that reduce clotting; these medicines are given to people with a higher chance of a condition of the heart or the brain. For a function test, you sometimes need to stop certain medicines, such as aspirin and ibuprofen. MedlinePlus writes that you should tell your healthcare provider about everything you take, and only stop if your healthcare provider tells you to.[1]
If you are pregnant, a mildly low value is common. MedlinePlus writes that this form usually gets better on its own during pregnancy or after the birth, and that this form is not known to cause harm.[1]
According to MedlinePlus, a value that is higher than normal can go with an illness caused by a virus or a bacterium, an inflammation of the bowel or of the joints, and anaemia. A value that is lower than normal can go with an illness caused by a virus, or with inflammation of or damage to the bone marrow.[1]
With a value that is higher than normal, MedlinePlus mentions heavy blood loss. With a value that is lower than normal, on the other hand, you can keep bleeding for a long time after a small cut or a wound.[1]
Platelets are included in all five packages, from BioProfile 31 to BioProfile 150.[4]
The BioProfile editorial team wrote this page on 30 September 2026 from the sources below, which we read on 30 September 2026. Every number on this page appears in one of those sources, with the number of that source next to it. An expert still has to review this page; after that review, the name of that expert and the date of the review appear at the top. This page gives an explanation, not a diagnosis. Discuss an abnormal value with your GP.
