(A) Platelet counts of blood collected with ethylenediaminetetraacetic acid (EDTA), heparin, and sodium citrate and examined at 0 min, 30 min, and 120 min after venipuncture. (B) Serotonin levels of the patient and a normal control subject in blood collected with EDTA examined at 30 min and 90 min after venipuncture.