[Occurrence and clinical relevance of thrombocytosis]

Automated routine platelet counting in 18,602 patients revealed thrombocytosis (platelet count above 400,000/mm3) in 9% (n = 1602) of cases. In 32% of the patients with thrombocytosis an acute or chronic inflammatory process was found, 9% had a malignant tumor and 9% anemia. 6% were alcoholics and 6% had a myeloproliferative syndrome. Chronic gastrointestinal disease was found in 4% and postoperative thrombocytosis in 3% of cases. 32% of the thrombocytosis cases could not be classified under any of the known causes of this disorder. In 51% of the cases the platelet count ranged from 400,000 to 450,000/mm3. Primary thrombocythemia often produced clinical symptoms, whereas secondary thrombocytosis almost always was asymptomatic.