RESUMEN
A 70 year-old woman was prescribed of levofloxacin and ceftriaxone for acute bronchitis. On the seventh day of administration she was hospitalized with a dry cough and a decreased platelet count(2.1 x 10(4)/microliter). However, bleeding tendency was not seen. So, we changed anticoagulants with citric acid and heparin from EDTA, and measured platelet count because we suspected pseudothrombocytopenia(PTCP), then platelet count became elevated (respectively, 12.5 x 10(4)/microliter and 15.0 x 10(4)/microliter). In addition, platelet associated IgG increased to 309.3 ng/10(7) cells. Based on drug lymphocyte stimulation test, she was diagnosed as having antibiotic-induced PTCP, especially as she had no history of thrombocytopenia. PTCP should be considered when thrombocytopenia occurs during antibiotic treatment.