Monday, 26 September 2011

Breath testing for 2-pentylfuran as a diagnostic test for pulmonary aspergillosis- an update

Breath testing methods to diagnose pulmonary aspergillosis is attractive because of the proximity of the infection (lung) and simplicity of obtaining samples for treatment. The detection of volatile organic compounds in the breath has been reported previously and 2-pentylfuran was isolated as a potential marker for aspergillus infections (link), also this compound is not produced by normal mammalian metabolism.
In May 2011, we ran a blog reporting initial data by Chambers et al that 2 pentylfuran could be detected in two immunocompromised patients with Aspergillus fumigatus infections. Initial studies also suggested that some foods which give rise to 2-pentylfuran may give false positive readings which would interfere with the tests.
A further report from the same group of researchers has determined new limits and possibilities for the potential breath test.
Of 45 foodstuffs tested 10 gave detectable 2-pentylfuran. Levels were highest from soymilk, lower from pumpkin, rolled oats, tinned asparagus, tinned beans and marmite. No 2-pentylfuran was detected from antifungal medicines. No difference in the time of day of testing or in relation to fasting or not, was observed. However the breath test could be accurately conducted on people who had ingested 2-pentylfuran positive foods - without an overnight fast -by simply rinsing the mouth with water - and waiting 30 mins or more before carrying out the breath test. The lower limits of detection were around 1 attogram of 2-pentylfuran.
This latest data decreases the problem of false positive results for this potentially diagnostic test.

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