DataSheet1_Investigating Factors of False-Positive Results of Aspergillus Galactomannan Assay: A Case–Control Study in Intensive Care Units.PDF

Background: Studies on false-positive galactomannan (GM) enzyme immunoassay (EIA) results and treatment for critically ill patients are scarce.
Objectives: The study aimed to determine the false-positive rate of GM-EIA and to probe the risk factors of false positivity among patients in the intensive care units (ICUs).
Methods: A case–control approach was conducted to review adult patients who had at least one GM-EIA result and were admitted to the ICU. Those who had no fungal culture were excluded. The clinical characteristics and critical care between patients with false-positive and true-negative GM index (GMI) were compared.
Results: Of 206 patients enrolled and with GM-EIA results, 20 (9.7%) were considered to have false-positive antigenemia, including 9 in bronchoalveolar lavages (BAL) and 11 in serum. A total of 148 (71.8%) were true-negatives. After paired grouping of 1:4, factors researched in the previous studies showed no significant difference. However, compared with the true-negatives, patients with positive GM test results but were incompatible with the diagnosis of invasive aspergillosis were more prone to the risk of false positivity due to the use of colistin inhalation. It seemed to be the only factor that significantly increased the risk of false positivity after multivariate analysis (adjusted odds ratio, 35.68; 95% CI, 3.77–337.51, p = 0.002).
Conclusions: Colistin inhalation treatment may contribute to false-positive GM-EIA results. The positive GMI among patients receiving colistin nebulization should be interpreted with caution.

背景：针对重症患者的半乳甘露聚糖（galactomannan, GM）酶免疫测定（enzyme immunoassay, EIA）假阳性结果及相关治疗的研究较为匮乏。
目的：本研究旨在明确重症监护病房（intensive care units, ICUs）患者中GM-EIA的假阳性率，并探究假阳性结果的相关危险因素。
方法：本研究采用病例对照研究方法，回顾性分析至少接受过1次GM-EIA检测且入住ICU的成年患者，排除未行真菌培养者，并对比假阳性与真阴性半乳甘露聚糖指数（GM index, GMI）患者的临床特征及重症救治情况。
结果：在纳入的206例拥有GM-EIA检测结果的患者中，20例（9.7%）被判定为假阳性抗原血症，其中支气管肺泡灌洗液（bronchoalveolar lavages, BAL）标本阳性9例、血清标本阳性11例；另有148例（71.8%）为真阴性结果。经1:4配对分组后，既往研究提及的相关危险因素未显示出显著差异。然而，与真阴性GMI患者相比，GM检测结果阳性但不符合侵袭性曲霉病（invasive aspergillosis）诊断的患者，因接受粘菌素（colistin）吸入治疗而出现假阳性结果的风险更高。经多变量分析证实，该因素是唯一显著升高假阳性风险的独立危险因素（校正比值比（adjusted odds ratio）为35.68；95%置信区间（95% CI）：3.77~337.51，P=0.002）。
结论：粘菌素吸入治疗可能与GM-EIA假阳性结果相关，对于接受粘菌素雾化吸入的患者，其GMI阳性结果需谨慎解读。