Platelet Count Test in Hari Nagar Ashram, Delhi

Platelets (thrombocytes) are tiny cell fragments made in the bone marrow that circulate in the blood and help it clot. When a blood vessel is injured, platelets rush to the spot, stick together and plug the leak. A platelet count measures how many of these cells are in a given volume of blood.

The test is widely known in India because of dengue, where platelet counts can fall sharply a few days into the illness and are monitored daily. But low platelets (thrombocytopenia) can have many other causes, including viral infections, malaria, certain medicines, autoimmune conditions, vitamin B12 or folate deficiency, liver disease, and bone marrow disorders. High platelets (thrombocytosis) are most often a reaction to iron deficiency, infection, inflammation or surgery, and less often a bone marrow disease.

Platelet count is part of a complete blood count (CBC), and it can also be requested alone for quick monitoring. Because platelets can clump in the test tube and give a falsely low reading, labs often confirm an unexpected low count by looking at a blood smear.

Platelets in dengue: what the numbers mean

In dengue, platelets typically start to fall from around day 3 to day 5 of fever, reach the lowest point around days 5 to 7 and recover as the fever settles. A low count alone is not an indication for transfusion. Doctors decide based on bleeding, falling counts with rising hematocrit, severe abdominal pain, persistent vomiting and other warning signs. Many patients with counts of 20,000–50,000 recover with fluids, rest and monitoring alone. Avoid aspirin and ibuprofen in suspected dengue, which can increase bleeding risk.

Other causes of low platelets

Immune thrombocytopenia (ITP), vitamin B12 or folate deficiency, liver disease with enlarged spleen, malaria, chikungunya, HIV, certain medicines, alcohol, pregnancy-related conditions and bone marrow problems can all lower platelets. A blood smear and further tests help separate these.

High platelets

Reactive thrombocytosis is common after infection, surgery or with iron deficiency, and usually settles after the cause is treated. Persistently very high counts may need tests for a bone marrow condition.

Platelet function matters too

Besides the count, platelets must work properly. Aspirin, clopidogrel and some conditions reduce function, which is why surgeons ask you about medicines before an operation.