A Breath Test to Diagnose Invasive Aspergillosis?

Summary and Comment |
November 4, 2014

A Breath Test to Diagnose Invasive Aspergillosis?

  1. Neil M. Ampel, MD

In a small study, a breath test distinguished patients with IA from those with pneumonia due to other causes with 94% sensitivity and 93% specificity.

  1. Neil M. Ampel, MD

Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunocompromised patients. Current methods of diagnosis, including culture and antigen detection, are insensitive. However, filamentous fungi such as Aspergillus produce an array of extracellular metabolites, including volatile organic compounds (VOCs). The type and pattern of these released compounds may be specific to particular fungi, and their detection and characterization could serve as a diagnostic tool.

To examine this possibility, researchers in Boston cultured several species of Aspergillus, including A. fumigatus (the most common cause of IA), under a variety of conditions and used gas chromatography with mass spectrometry to characterize the pattern of released VOCs. They then collected breath samples over a 4-minute period from 64 patients with pneumonia, 33 of whom had proven or probable IA by the revised European Organization for Research and Treatment of Cancer/Mycoses Study Group consensus criteria (the reference standard). Most patients had received antifungal therapy prior to breath sampling.

With use of the breath test, 34 patients (including 1 classified by the reference standard as having “possible IA” but determined after death to have IA) ultimately received a diagnosis of IA. Finding any of four Aspergillus-associated metabolites in the breath of patients with pneumonia identified IA with 94% sensitivity and 93% specificity compared with the reference standard.

Comment

This small investigational study suggests that a noninvasive breath assay for VOCs released by Aspergillus species could become a viable diagnostic test. Further studies are needed, including ones involving other fungal infections and examining patient breath samples prior to antifungal therapy.

Editor Disclosures at Time of Publication

  • Disclosures for Neil M. Ampel, MD at time of publication Editorial boards Medical Mycology Leadership positions in professional societies Coccidiodomycosis Study Group (President-Elect)

Citation(s):

Reader Comments (2)

Brian Mahood MA MB FRACP Physician, Pulmonary Medicine, Waikato Hospital, NZ

I am glad that someone has developed a non-invasive test measuring Aspergillus metabolites in exhaled air using a gas chromatograph. Easier, and more sensitive and specific. Much better, accurate and safer than bronchial brushings, washings, microscopy and COS.

Beatriz Bustamante

Estimada Beatríz,

Algo así es lo que quisieramos evaluar en Pneumocystis.
Saludos,

Sergio Vargas

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