Platelets
and Eva Rudolf-Müller, doctorDr. med. Andrea Reiter is a freelance writer for the medical editorial team.
More about the expertsEva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.
More about the experts All content is checked by medical journalists.The platelets (blood platelets) play an important role in stopping bleeding. However, they can also be responsible for the formation of blood clots (thrombi), which can cause pulmonary embolism and strokes, among other things. Read everything you need to know about platelets and their importance as a laboratory value!
What are platelets?
Platelets are small, two to four micrometers large, disc-shaped cell bodies that float freely in the blood. They don't have a nucleus.
Platelets play an important role in stopping bleeding (primary hemostasis) - the first step in blood clotting. If a blood vessel is injured, for example by a cut with a knife, they attach to the injured vessel wall. More and more blood platelets adhere to these platelets. This so-called platelet aggregation quickly closes the vascular leak and the bleeding stops. The closure is stabilized by further processes (secondary hemistasis).
Platelets typically live five to nine days and are then discarded in the spleen, liver, and lungs. The normal platelet levels in newborns and adolescents are different from those in adults.
When is the platelet count?
The number of platelets is determined in the following cases:
- when a patient is bleeding more than normal
- as part of a routine blood test (small blood count)
- before and after operations
- during therapy with blood-thinning agents or chemotherapeutic agents
- in patients with thrombosis
- if blood clotting disorders are known or if platelet function disorders are suspected (thrombocytopathies)
Platelet counts
The number of platelets depends on age. The following standard values apply (for adults per microliter of blood, for children and adolescents per nanoliter of blood):
|
age |
Normal platelet value |
|
adult |
150,000 - 400,000 / µl |
|
up to 9 months of age |
100 - 250 / nl |
|
1st to 6th year of life |
150 - 350 / nl |
|
7 to 17 years of age |
200 - 400 / nl |
When are there too few platelets in the blood?
Occasionally the number of platelets in the blood is decreased. This can have different causes. Either the body does not produce enough platelets or they perish more often. Then one speaks of thrombocytopenia or thrombopenia - here you can find out more about it!
When are there too many platelets in the blood?
An increased number of platelets is called thrombocytosis. It can occur in various diseases and is also dangerous from a certain height. Read more about thrombocytosis here!
What to do if the platelet count changes
If the number of platelets in the blood changes, the reason must be found. In the vast majority of cases, it is an accompanying phenomenon to an infection. Once it has subsided, the platelet count quickly returns to normal.
More rarely, other causes such as a disturbance in platelet formation or a malignant disease can also be behind deviating measured values. The cause can usually be found quickly with further blood tests, physical examinations or imaging tests. If the underlying disease is treated correctly, the number of platelets usually regulates itself in a row.
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