Blood Test

Platelet Count

Platelets are tiny blood cells that stop bleeding by forming clots. Too few platelets means you bleed easily: too many can cause dangerous clots. Here's what your count means.

Written and clinically reviewed by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: 01 August 2026 · How we check our content

Platelet Count Normal Range

Status	Count (per µL or /mm³)
Normal	150,000 – 400,000
Mild thrombocytopenia	100,000 – 150,000
Moderate thrombocytopenia	50,000 – 100,000
Severe thrombocytopenia	20,000 – 50,000
Critical: bleeding risk	<20,000
High (thrombocytosis)	>400,000

What does LOW platelet count mean?

LOW Platelets below 150,000: Thrombocytopenia

Low platelets (thrombocytopenia) increase the risk of bruising and bleeding. Common causes: Dengue fever (a common acute cause in endemic regions, platelets can drop rapidly within 3–5 days of fever), viral infections (chikungunya, malaria, typhoid), ITP (Immune Thrombocytopenic Purpura, immune system destroys platelets), liver disease (spleen enlargement traps platelets), medications (heparin, chemotherapy, some antibiotics), bone marrow disorders, vitamin B12/folate deficiency.

When to go to hospital urgently: Platelets below 20,000, OR any platelet level with active bleeding (blood in urine, black stools, bleeding gums, petechiae, tiny red spots on skin).

What does HIGH platelet count mean?

HIGH Platelets above 400,000: Thrombocytosis

Reactive thrombocytosis (most common): platelets rise in response to infection, inflammation, iron deficiency anaemia, surgery or physical stress. The platelet count returns to normal once the trigger resolves, no treatment needed. Primary thrombocytosis (rare): a bone marrow disorder causes the marrow to produce excess platelets regardless of need (essential thrombocythaemia). Very high platelets (>10,00,000) can paradoxically cause bleeding rather than clotting in some conditions.

Questions to ask your doctor

Is my low platelet count from dengue? Should I monitor daily?
Do I need a bone marrow test?
Which of my medications could be causing this?
At what platelet level do I need a transfusion?

Frequently Asked Questions

What does a low platelet count mean?

A low count (thrombocytopenia) increases bruising and bleeding risk. Causes range from viral infections and medications to immune conditions and bone marrow disorders, so the trend and other blood counts guide investigation.

What causes a high platelet count?

High platelets (thrombocytosis) are most often a reaction to infection, inflammation, or iron deficiency, and less commonly reflect a bone marrow disorder. Repeat testing helps distinguish these.

When is a platelet count an emergency?

Very low counts with active bleeding, or a high count with clotting symptoms (chest pain, breathlessness, stroke signs), need urgent assessment.

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

Platelet Transfusion. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK560632