醫療診斷除了評估臨床症狀外，還需參考相關醫學檢驗值才能進行，錯誤的檢驗值會混淆醫師診斷方向，導致病患無法獲得合適的治療處置。使用Platelia Aspergillus Enzyme Immunoassay (EIA) 試劑進行半乳甘露聚糖 (galactomannan, GM) 血清抗原檢測，piperacillin-tazobactam 可能使結果呈偽陽性。本案例為一位有慢性阻塞性肺病、逆流性食道炎、右上肺葉腫塊病史的63 歲男性，因呼吸急促疑似繼發性感染，給予piperacillin-tazobactam 靜脈點滴滴注，治療九日後病況不見好轉，懷疑感染侵入性麴菌症，半乳甘露聚糖血清抗原檢測結果呈陽性反應，但評估臨床症狀後排除麴菌感染可能性，推測該檢驗結果為piperacillin-tazobactam 所導致之偽陽性反應。

The medical diagnosis is not only assess clinical symptoms and diagnostic testing, but also laboratory examination. The incorrect laboratory examination makes the practitioners confused when proceeding differential diagnosis, which probably leads to unsuitable medical management. Patients receiving piperacillin-tazobactam could results Aspergillus serum galactomannan enzyme immunoassay (EIA) false-positive. This case of 63-year-old male, who had Chronic obstructive pulmonary disease (COPD), reflux esophagitis and right upper lobe bronchogenic adenocarcinoma. Due to COPD with acute exacerbation and secondary infection, he was treated with piperacillintazobactam. After nine days treatment, the situation got worse. At the moment, the practitioner considered invasive aspergillosis infection, so we examined Aspergillus Serum Galactomannan Enzyme Immunoassay. Evaluating of the patient and reviewing other similar case reports, we suggested the positive result was associated with using piperacillin-tazobactam. In the end, the patient discharged without receiving antifungal therapy.