Antigen Assay with the Potential To Aid in Diagnosis of Blastomycosis

Abstract

We report results of an immunoassay for Blastomyces dermatitidis antigenuria. Sensitivity was 92.9%, and specificity was 79.3%. Cross-reactions occurred in 96.3% of patients with histoplasmosis, 100% of patients with paracoccidioidomycosis, 70% of patients with penicilliosis marneffei, 2.9% of patients with cryptococcosis, and 1.1% of patients with aspergillosis. Reproducibility was 96.3%. These findings support a potential role for antigen testing in blastomycosis.Most patients with blastomycosis exhibit progressive illnesses that require antifungal therapy. In one study, diagnosis was delayed for more than 1 month in nearly half of the cases (3). Blastomycosis was correctly suspected in only 20% of patients, resulting in unnecessary surgeries and treatment delays (7). In two-thirds of patients who died of acute respiratory distress syndrome caused by blastomycosis, the diagnosis was either not suspected or considered only after the patient became moribund (10).At the University of Mississippi Medical Center, the first testing method for diagnosis was cytology in 58% of cases, KOH in 28% of cases, and histology in 12% of cases (8). The overall sensitivities were 93% for cytology, 85.1% for histology, 66.4% for culture, and 48.4% for KOH preparation. Pathologists who are less experienced with morphological

Serum and UrineBlastomycesAntigen Concentrations as Markers of Clinical Remission in Dogs Treated for Systemic Blastomycosis

“…Similar to prior reports in people and dogs,7, 8, 9, 10 we found urine Blastomyces antigen to be highly sensitive for the diagnosis of blastomycosis (100% sensitivity in this population). The sensitivity for serum antigen test was also quite high (about 90%), which is similar to previous reports (87%) 8.…”

“…In the absence of organism identification, diagnosis has been accomplished historically through a combination of clinical signs, radiographic findings, and serum antibodies 2, 4, 5, 6. Recently an antigen test has been developed, which detects a cell wall galactomannan, and has been found to have a high degree of both sensitivity and specificity for the diagnosis of blastomycosis in dogs and humans 7, 8, 9, 10. Although both urine and serum can be assayed to evaluate the presence of Blastomyces antigen, urine antigen measurement appears to have an increased sensitivity relative to serum antigen for the diagnosis of blastomycosis in dogs 8…”

Systemic Blastomycosis Diagnosed by Prostate Needle Biopsy

“…2,4,5,26,27 Antigen detection in urine or other body fluids for B. dermatitidis is reported as sensitive with high reproducibility however cross reactivity with other mycoses may prohibit clear diagnosis. [28][29][30] The WI-1 antigen based antibody test has good sensitivity and specificity but is not widely available. 31 Antigen detection can be useful to monitor treatment efficacy in patients with disseminated blastomycosis.…”

Comparison of antibody detection with <i>Blastomycesdermatitidis</i> yeast lysate antigens in serum specimens from immunized rabbits and infected dogs

“…In recent years, there has been an adamant thrust in understanding the proper diagnosis of this disease because blastomycosis is often misdiagnosed that can create treatment delays [10][11][12][13][14]. As with many other diseases, time is of particular importance in terms of diagnosis and treatment [15,16].…”