12.一位21歲男性病人主訴運動後呼吸急促，尿液呈深褐色但無bilirubinuria亦無紅血球。血液檢查顯示Hb 8.6 g/dL，WBC 4,750/μL，platelet 156,000/μL，total bilirubin3.5 mg/dL，direct biliubin 0.7 mg/dL，AST105 U/L(正常＜31)，ALT 32U/L(正常＜31)，LDH 1,250 U/L(正常230-460)。下列何種檢查對診斷是最不必要的？
(A)HBsAg
(B)Reticulocyte
(C)Coombs' test
(D)Glucose-6-phosphate dehydrogenase
(E)Flow cytometry for CD55 and CD59 expression of blood cells