Sensitivity and specificity of a blood and urine galactomannan antigen assay for diagnosis of systemic aspergillosis in dogs.

BACKGROUND

Diagnosis of canine systemic aspergillosis requires fungal culture from a sterile site, or confirmatory histopathology from a nonsterile site. Invasive specimen collection techniques may be necessary.

OBJECTIVE

To evaluate the sensitivity and specificity of a serum and urine Aspergillus galactomannan antigen (GMA) ELISA assay for diagnosis of systemic aspergillosis in dogs.

DESIGN

Multicenter study.

ANIMALS

Thirteen dogs with systemic aspergillosis and 89 dogs with other diseases. Thirty-seven of the 89 dogs had signs that resembled those of systemic aspergillosis and 52 dogs were not suspected to have aspergillosis.

PROCEDURE

The GMA ELISA was performed on serum specimens from all dogs and urine specimens from 67 dogs. Galactomannan indices (GMI) ≥ 0.5 were considered positive. Results for dogs in each group were compared.

RESULTS AND CONCLUSIONS

The sensitivity and specificity of the assay for serum were 92 and 86%, respectively, and for urine were 88 and 92%, respectively. False negatives were seen only in dogs with localized pulmonary aspergillosis. Use of a cutoff GMI of 1.5 increased specificity to 93% for both serum and urine without loss of sensitivity for diagnosis of disseminated infection. High-level false positives (> 1.5) occurred in dogs with other systemic mycoses and those treated with Plasmalyte.

CLINICAL RELEVANCE

Serum and urine Aspergillus GMA ELISA is a noninvasive, sensitive, and specific test for the diagnosis of disseminated aspergillosis in dogs when a cutoff GMI of ≥ 1.5 is used.