Thrombocytosis

Q: By definition, thrombocytosis is platelet count more than? (select one)

A) >350,000/microL
B) >450,000/microL


Answer: B

By definition, normal platelet count - both in adults and pediatric population - is 150,000 to 450,000/microL. Any count above 450,000/microL is described as thrombocytosis. 

Broadly they are divided into two classes according to it causes 

1. Reactive which is due to anemia, infections, inflammation, drug-induced, trauma, or asplenia 
2. Autonomous which is also known as primary thrombocytosis which is due to any pathology in mechanisms that lay within the megakaryocyte or its precursor cells. Two major causes in this class besides mutations are hematologic malignancies and familial thrombocytosis.


#hematology


References:

1. Bleeker JS, Hogan WJ. Thrombocytosis: diagnostic evaluation, thrombotic risk stratification, and risk-based management strategies. Thrombosis. 2011;2011:536062. doi:10.1155/2011/536062 

2. Skoda RC. Thrombocytosis. Hematology. 2009:159–167.