Determining the number of platelets (platelet count) is a routine blood test. The doctor prescribes it to diagnose a blood disease or a bleeding disorder.

Also called thrombocytes, platelets are cells without nuclei, 2 to 4 microns, produced by the bone marrow. They are part of the blood, along with red blood cells (also called red blood cells) and white blood cells (also known as white blood cells).

They intervene in the process of coagulation, a phenomenon essential to the protection of the vascular system.

It is in the initiation that it intervenes more precisely: the first stage necessary to the stop of a hemorrhage begins with the adhesion of the platelets to the wall of the damaged blood vessel. Then they aggregate and release their content. It is then the formation of the “platelet nail”, which plugs the breach in the blood vessel.

In other words, when you cut yourself, the platelets are used to fill the gaps in the damaged blood vessels and thus prevent too much bleeding.

The doctor prescribes a platelet test, called a platelet count, if he suspects his patient has a blood disease or coagulation disorders.

This analysis is part of a more comprehensive test called a complete blood count or Blood Formula Count (CBC), which is routinely offered to assess a patient’s general health. The number of red blood cells and white blood cells is also determined in this test.

The normal platelet count is between 150 and 000 / mm450 (per cubic millimeter) of blood.

An increase in the number of platelets (called thombocytosis) may be a sign of:

• inflammation;
• an infection ;
• iron deficiency leading to anemia;
• the presence of severe burns;
• significant stress;
• a cirrhosis ;
• splenectomy (i.e. removal of the rate)
• significant bleeding (whether internal or external);
• or even bone marrow stimulation.

On the contrary, a decrease in the number of platelets (this is called thrombocytopenia) can mean:

• damage to the bone marrow, and in particular bone marrow aplasia (that is to say, the cessation of production of blood cells normally synthesized by the bone marrow);
• an autoimmune disease (when the immune system fights against cells in the body, believing they are foreign cells);
• acute alcoholism;
• un purpura (ie a hard dermatological lesion at an exit of the red blood cells from the blood vessels to the surrounding tissues);
• drug toxicity;
• or a viral infection (such as hepatitis, chickenpox, mumps, measles or even mononucleosis).

A thombocytopenia can in turn be the source of various ailments. These include:

• nosebleed;
• ahemorrhage GUM, digestive or at the level of other organs;
• the appearance of bruises;
• headaches ;
• or even double vision.

The examination consists of a venous blood sample, usually at the bend of the elbow.

Note that in addition, the doctor can prescribe an analysis of their aggregation and a measurement of the bleeding time.

Certain physiological situations can cause a platelet count higher or lower than normal. Let us quote for example:

• pregnancy, when there are fewer platelets;
• alcohol consumption (which lowers the number of platelets);
• a prolonged effort or the fact of living at altitude, which increase the number of platelets.

It is therefore important to discuss this with the medical staff.