Platelet 303*10⁹/L is a little on the high side, but the exact clinical significance should be determined by the patient’s condition. Normal adult platelet count is (100~300)×10⁹/L, higher than 300×10⁹/L is high. Elevated platelet counts are categorized into primary thrombocytosis and secondary thrombocytosis. Primary thrombocytosis is often seen in myeloproliferative disorders, hematologic disorders, etc. Secondary thrombocytosis is commonly seen in infections, inflammation, tumors, splenectomy, pregnancy, procoagulant drugs, etc. Elevated platelets are abnormal, platelets 303 × 10⁹ / L is a little higher, but if a single indicator is high, there are no symptoms, the clinical significance is not great, should be combined with the clinical characteristics and related laboratory indicators to determine the synthesis. If the platelets continue to rise, then we need to pay attention to, recommend hospital consultation, if necessary, improve the relevant laboratory tests, a clear diagnosis.