Platelet Count

Other names: Thrombocyte Count

The platelet count is carried out as part of the series of tests that make up the full blood count. Platelets are produced by the bone marrow and are involved in the activation of the blood clotting process; they are tiny fragments of cells, which travel around in the blood. The platelet count shows the amount of platelets in the blood.

Why is the test used?

The platelet count is carried out as part of a full blood count; it may be ordered as part of a routine blood test or as a means of determining the cause of unexplained bruising or bleeding.

The test is usually ordered when a patient has bruising which takes a long time to heal or experiences persistent bleeding, which takes a long time to stop.

How is the test carried out?

The test is performed by taking a sample of blood from a vein in the arm; a needle is inserted into the vein and the blood is drawn out and collected in a syringe. When the doctor has a sufficient sample, the blood will be placed in a bottle and labelled with the patient’s name; the sample is then sent away to the laboratory for analysis.

What do the test results show?

The test results show the amount of platelets in the blood; a normal measurement is between 150,000 and 400,000 platelets per microlitre of blood.

If the result is much lower than normal this may indicate that the patient has a problem which is affecting the bone marrow; examples of conditions include leukaemia or cancer of the bone marrow. Patients with autoimmune diseases, such as lupus, may also have a low platelet count because their body attacks and destroys the platelets. Treatments such as chemotherapy may also cause platelet numbers to decrease.

If the result shows that there are more platelets than normal, this may be associated with a condition known as myeloproliferative disorder, which affects the growth of the blood cells; however, this is rare. Most people with a high platelet count do not suffer from symptoms.

People who live in high altitudes usually have a higher platelet count. Levels may also increase after strenuous physical exercise. Taking medication, such as oral contraceptives and oestrogen may also cause levels to increase.

Levels may decrease prior to menstruation.

Specific Blood Tests

© Medic8® | All Rights Reserved