This patient presents with signs and symptoms of aplastic anemia, namely fatigue, pallor, dyspnea, petechiae, and tachycardia. Aplastic anemia is associated with patients taking chloramphenicol. Laboratory findings of aplastic anemia include neutropenia, anemia, and thrombocytopenia (low platelet count). This patient does not have any known thyroid problem or symptoms, so a low TSH is unlikely. There is also no reason this patient should have elevated liver function tests (AST, ALT).