Low Platelets (Thrombocytopenia): Causes and Next Steps

Low platelets (thrombocytopenia) means your platelet count is below 150,000 per microlitre. A small drop is often brief and harmless, from a virus, a medicine or a problem with the sample. If the count is very low, or you have bruises, bleeding gums or tiny red spots on the skin, see a doctor soon. This guide is by Dr. Pedro Yelamo Vera, a GP licensed in Spain (Colegiado No. 484814280).

What platelet count is low?

Platelets are tiny cell pieces that help seal cuts. They are measured in a full blood count. Reports often show them in thousands per microlitre (× 10³/µL), so "120" means 120,000. UK reports use × 10⁹/L, which gives the same number.

MedlinePlus gives 150,000 to 400,000 as normal. Below 150,000 is low, called thrombocytopenia. Each lab sets its own range, which can vary a little, so check the one next to your result. An "L" or a star means it is below range. In a Spanish report, look for plaquetas in the hemograma.

What does a slightly low platelet count mean?

A count between 100,000 and 150,000 is common and often means little. Repeating the test a few weeks later is usually enough, mainly if you had a cold or a virus. If it stays low or falls further, the doctor looks for a cause.

Could it be a lab error?

Yes. In some people, platelets clump together in the usual tube (EDTA). The machine counts each clump as one platelet, so the result looks too low. This is called pseudothrombocytopenia. It is checked by looking at the blood under a microscope, or by repeating the test in a citrate tube. It needs no treatment.

What causes low platelets?

MedlinePlus puts the causes in three groups: the bone marrow makes fewer, the body uses them up faster, or the spleen holds on to them. The most common are:

• Viral infections, such as flu, glandular fever, HIV or hepatitis C.
• Medicines, such as heparin, some antibiotics or epilepsy medicines, and chemotherapy.
• Heavy drinking and liver disease, such as cirrhosis, which make the spleen bigger.
• Immune thrombocytopenia (ITP), where the immune system destroys platelets.
• Low vitamin B12 or folate.
• Pregnancy: gestational thrombocytopenia is common, usually mild, and comes late on.
• Less often, bone marrow disease, such as leukaemia.

What are the symptoms of low platelets?

With a mild drop, there are none. When the count falls further you may see:

• Bruising easily, or without a knock.
• Petechiae: tiny red or purple dots on the skin, often on the legs, that do not fade when pressed.
• Bleeding gums or nosebleeds.
• Heavier periods.
• Blood in your urine or stools.

Is a low platelet count serious?

It depends on the number and the cause. Above 50,000, bleeding in daily life is rare. The MSD Manual says that between 20,000 and 50,000 bleeding happens mainly after an injury, and below 20,000 bleeding can happen with no cause. It also matters whether your white cells and haemoglobin are normal. If all three are low together, it needs a check sooner. Read about a low white blood cell count and the full blood count.

What tests come next?

• A repeat blood count, sometimes in a citrate tube.
• A blood film, to look at the platelets under a microscope.
• Vitamin B12, folate and liver tests.
• Tests for viruses such as HIV and hepatitis C.
• If there is still no cause, or the count is very low, a blood specialist (haematologist).

What should I do in the meantime?

Do not stop any medicine on your own, but tell your doctor about everything you take, including herbs and supplements. Ask before taking aspirin or anti-inflammatories such as ibuprofen, because they affect how platelets work. Avoid alcohol. If your count is very low, your doctor will tell you whether to avoid contact sports. You can compare with our guide to high platelets.

When to go to A&E or call 112

• Bleeding that will not stop after 10 minutes of pressure.
• Black, tarry stools, or vomiting blood.
• A sudden bad headache, confusion or drowsiness.
• Red or purple spots that spread, above all with a fever.
• A very low count on your test, even if you feel well.

Frequently asked questions about low platelets

Getting a medical assessment

If you are in Spain and have a low platelet count, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain, to go over your results. You can also read about blood test results explained. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.