612. Serum Galactomannan Testing in Patients On Highly-Active Mold Prophylaxis
Session: Abstracts: Mycology
Friday, October 22, 2010
Background:

Serum galactomannan monitoring in at-risk HSCT recipients has been used as a surveillance test to allow early identification of invasive aspergillosis (IA).   However the sensitivity of the assay has been shown to be reduced by concomitant mold-active antifungal agents but has not been studied in patients on highly-active mold prophylaxis (HAMP) such as voriconazole, posaconazole or echinocandins.  We theorized that there would be very little utility of screening galactomannan in patients on HAMP.

Methods:

We performed a systematic review of all unrelated allogeneic HSCT and cord blood recipients at the University of Michigan who had a serum galactomannan assay performed between July 1st, 2006 and July 1st, 2008 and were on HAMP at the time of the galactomannan assay.

Results:

A total of 1,277 galactomannan assays were sent on 162 HSCT recipients on HAMP at time of the assay. Excluding serum galactomannan as part of the MSG diagnostic criteria, 2 cases of IA developed while on HAMP.  Galactomannan assays were falsely negative in both.  

However, if a positive serum galactomannan is utilized as part of the MSG diagnostic criteria (revised MSG criteria), an additional 5 cases of probable IA were confirmed.  Galactomannan testing correctly identified 5/7 cases of proven or probable IA in patients on HAMP.  However, in all five patients positive serum galactomannans were made either concurrent with or after the appearance of radiologic findings consistent with the already suspected clinical diagnosis of IFI.

Conclusion:

As a surveillance strategy, routine monitoring of serum galactomannan in patients on HAMP is unlikely to lead to the early identification of break-through IA.  However, in patients with other findings suggestive of IFI, the use of galactomannan was helpful in defining the pathogen and/or establishing an eventual diagnosis in patients on HAMP using revised MSG criteria.


Subject Category: M. Mycology including clinical and basic studies of fungal infections

Speakers:
Eric Cober, MD , University of Michigan, Ann Arbor, MI
Daniel Kaul, MD , University of Michigan Medical School, Ann Arbor, MI
Jeannina Smith, MD , University of Michigan, Ann Arbor, MI

Disclosures:

E. Cober, None

D. Kaul, None

J. Smith, None

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