Re: New Antigen-Based Tests For Invasive Fungal Disease

[Guest guest]

so would these tests be something to do in addition to the realtime labs

mycotoxin urine test? sue

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>Assays for Invasive Fungal Disease

>Two new antigen-based tests show promise and could prove useful for

>immunocompromised patients.

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>Early diagnosis and therapy is critical to the management of patients

>with invasive fungal disease (IFD). Although diagnosis has been based on

>culture or microscopy, antigen-based assays to detect (13)-$)A & B-D-glucan

>(BG) and Aspergillus galactomannan recently became available. Both rely

>on identification of polysaccharides associated with the cell wall of

>fungal pathogens. Now, two research groups have examined the performance

>and usefulness of these assays in patients at risk for IFD.

>Koo and colleagues retrospectively reviewed the results of 1308 serum BG

>assays performed for 871 patients. For patients tested more than once,

>the results of the first BG test were used. A BG level 80 pg/mL had a

>sensitivity of 64% and a specificity of 84% for a diagnosis of IFD

>within 1 week. Sensitivity was 71% and specificity was 81% for such a

>diagnosis by the end of hospitalization. Albumin, intravenous

>immunoglobulin, and hemodialysis independently increased BG levels. When

>patients with these factors were excluded from analysis, the specificity

>of the test increased slightly, but the sensitivity remained unchanged.

>Maertens and colleagues examined the use of the Platelia Aspergillus

>galactomannan assay on bronchoalveolar lavage (BAL) fluid from patients

>hospitalized for hematologic disorders. (One of the authors has received

>support from the assay maker.) Among 99 BAL samples, the mean optical

>density for the assay was 4.3 for 58 patients with proven or probable

>invasive pulmonary aspergillosis (IPA) compared with 0.6 for 41 controls

>without this diagnosis. At an optical density 1.0, sensitivity was 91%

>and specificity was 88% for diagnosing IPA. For culture or microscopy,

>the sensitivity was only 74%.

>Comment: These reports indicate the value of newer, antigen-based

>techniques for diagnosing IFD. Because neither assay depends on host

>immune response, both are useful for immunocompromised patients.

>Although caveats remain regarding their interpretation, these tests are

>important additions to our armamentarium.

>$)A!* Neil M. Ampel, MD

>Published in Journal Watch Infectious Diseases November 18, 2009

>Citation(s):

>Maertens J et al. Bronchoalveolar lavage fluid galactomannan for the

>diagnosis of invasive pulmonary aspergillosis in patients with

>hematologic diseases. Clin Infect Dis 2009 Dec 1; 49:1688.

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>Medline abstract (Free)

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>Koo S et al. Diagnostic performance of the (13)-$)A & B-D-glucan assay for

>invasive fungal disease. Clin Infect Dis 2009 Dec 1; 49:1650.

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>Medline abstract (Free)

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