Aspergillus Galactomannan Antigen Detection, Bronchoalveolar Lavage or Serum

Serum or bronchoalveolar lavage (BAL)

2 mL

0.35 mL (Note: This volume does not allow for repeat testing.)

Serum: Red-top tube or gel-barrier tube; BAL: sterile screw-cap, leakproof container

Caution against submitting pour-off specimens or specimens sent in non-sterile containers as this can lead to false positive results.

Usual aseptic technique

Patients diagnosed with chronic granulomatous disease and/or Job's syndrome may yield a reduced detection of galactomannan.¹ Reduced assay sensitivity may occur in patients receiving concomitant antifungal therapy.² Penicillium species, Alternaria species, Paecilomyces species, Geotrichum species, and Histoplasma species have demonstrated reactivity with the monoclonal antibodies used in the assay and may, therefore, yield a positive test result. Positive results in patients with no clinical signs of disease have been reported, especially in young children.³ Most of these are considered to be false positives. Young children may have a positive assay result due to the presence of galactofuranaase contained in various foods (cereals) and milk. Patients receiving piperacillin/tazobactam or semisynthetic beta-lactamase therapy may have false-positive results.^4,5 False-positive results may also occur with use of PLASMA-LYTE™ for either intravenous hydration or BAL specimen collection.⁶

A negative result does not exclude the possibility of invasive aspergillosis. Patients at risk for invasive aspergillosis should be tested twice weekly. Results close to the cutoff (ie, index of 0.5) should be interpreted with caution and supported by clinical, radiological, or laboratory culture results. BAL samples with an index value between 0.5 and 1.0 have a lower predictive value than those with a value >1.0.

Enzyme immunoassay (EIA)