False positivity of the Aspergillus galactomannan Platelia ELISA because of piperacillin/tazobactam

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False positivity of the Aspergillus galactomannan Platelia ELISA because of piperacillin/tazobactam treatment: does it represent a clinical problem?

J Antimicrob Chemother. 2008 Jul 21;

Authors: Orlopp K, von Lilienfeld-Toal M, Marklein G, Reiffert SM, Welter A, Hahn-Ast C, Purr I, Gorschlüter M, Molitor E, Glasmacher A

Objectives False-positive results of the galactomannan (GM) ELISA caused by concurrent administration of piperacillin/tazobactam have been reported in patients with febrile neutropenia. Patients and methods This prospective study investigated different sampling times in 30 patients receiving piperacillin/tazobactam for febrile neutropenia. Results Prior to the first piperacillin/tazobactam infusion, a median GM index of 0.2 [interquartile range (IQR) 0.1-0.3] was noted; in two patients (7%) the index was 0.5. Immediately after piperacillin/tazobactam infusion, the median index increased to 0.3 (IQR 0.2-0.4, P = 0.002) leading to 21% (7/30) false-positive results, if >/=0.5 is assumed as the cut-off level. GM indices before the next piperacillin/tazobactam infusion were not increased (median 0.2, IQR 0.2-0.35, P > 0.05), but 10% (3/30) were still >/=0.5. With a cut-off level of >0.7, no false-positive results were noted at any sampling time point. Conclusions We conclude that the clinical relevance of false-positive GM results during piperacillin/tazobactam treatment is small if samples are collected prior to infusion and if a cut-off level of >0.7 is used.

PMID: 18647743 [PubMed - as supplied by publisher]

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