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Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay Patricia Connolly a , Chadi A. Hage b , J. Ryan Bariola c , Eric Bensadoun d , Mark Rodgers a , Robert W. Bradsher Jr. c and L. Joseph Wheat a a MiraVista Diagnostics, Indianapolis, Indiana, USA b Indiana University School of Medicine and Roudebush Veterans' Administration Medical Center, Pulmonary Critical Care Medicine, Indianapolis, Indiana, USA c Division of Infectious Diseases, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA d Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky, Lexington, Kentucky, USA ABSTRACT The second-generation MVista Blastomyces antigen enzyme immunoassay was not quantitative; therefore, specimens obtained previously were tested in the same assay as new specimens to assess the change in antigen levels. Furthermore, the sensitivity in serum had not been fully evaluated. The purpose of this study was to evaluate a quantitative Blastomyces antigen assay and detection of antigen in serum. Calibrators containing known concentrations of Blastomyces galactomannan were used to quantify antigen in urine and serum from patients with proven blastomycosis and from controls. Paired current and previously obtained urine specimens were tested to determine if quantification eliminated the need for concurrent testing to assess change in antigen. Pretreatment of serum with EDTA at 104°C was evaluated to determine if dissociation of immune complexes improved detection of antigenemia. Antigenuria was detected in 89.9% of patients with culture- or histopathology-proven blastomycosis. Specificity was 99.0% in patients with nonfungal infections and healthy subjects, but cross-reactions occurred in 95.6% of patients with histoplasmosis. Change in antigen level categorized as increase, no change, or decrease based on antigen units determined in the same assay agreed closely with the category of change in ng/ml determined from different assays. Pretreatment increased the sensitivity of detection of antigenemia from 35.7% to 57.1%. Quantification eliminated the need for concurrent testing of current and previously obtained specimens for assessment of changes in antigen concentration. Pretreatment increased the sensitivity for detection of antigenemia. Differentiation of histoplasmosis and blastomycosis is not possible by antigen detection. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Clinical and Vaccine Immunology American Society For Microbiology

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay

Clinical and Vaccine Immunology , Volume 19 (1): 53 – Jan 1, 2012

Abstract

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay Patricia Connolly a , Chadi A. Hage b , J. Ryan Bariola c , Eric Bensadoun d , Mark Rodgers a , Robert W. Bradsher Jr. c and L. Joseph Wheat a a MiraVista Diagnostics, Indianapolis, Indiana, USA b Indiana University School of Medicine and Roudebush Veterans' Administration Medical Center, Pulmonary Critical Care Medicine, Indianapolis, Indiana, USA c Division of Infectious Diseases, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA d Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky, Lexington, Kentucky, USA ABSTRACT The second-generation MVista Blastomyces antigen enzyme immunoassay was not quantitative; therefore, specimens obtained previously were tested in the same assay as new specimens to assess the change in antigen levels. Furthermore, the sensitivity in serum had not been fully evaluated. The purpose of this study was to evaluate a quantitative Blastomyces antigen assay and detection of antigen in serum. Calibrators containing known concentrations of Blastomyces galactomannan were used to quantify antigen in urine and serum from patients with proven blastomycosis and from controls. Paired current and previously obtained urine specimens were tested to determine if quantification eliminated the need for concurrent testing to assess change in antigen. Pretreatment of serum with EDTA at 104°C was evaluated to determine if dissociation of immune complexes improved detection of antigenemia. Antigenuria was detected in 89.9% of patients with culture- or histopathology-proven blastomycosis. Specificity was 99.0% in patients with nonfungal infections and healthy subjects, but cross-reactions occurred in 95.6% of patients with histoplasmosis. Change in antigen level categorized as increase, no change, or decrease based on antigen units determined in the same assay agreed closely with the category of change in ng/ml determined from different assays. Pretreatment increased the sensitivity of detection of antigenemia from 35.7% to 57.1%. Quantification eliminated the need for concurrent testing of current and previously obtained specimens for assessment of changes in antigen concentration. Pretreatment increased the sensitivity for detection of antigenemia. Differentiation of histoplasmosis and blastomycosis is not possible by antigen detection.

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Publisher
American Society For Microbiology
Copyright
Copyright © 2012 by the American society for Microbiology.
ISSN
1556-6811
eISSN
1556-679X
DOI
10.1128/CVI.05248-11
pmid
22116687
Publisher site
See Article on Publisher Site

Abstract

Blastomyces dermatitidis Antigen Detection by Quantitative Enzyme Immunoassay Patricia Connolly a , Chadi A. Hage b , J. Ryan Bariola c , Eric Bensadoun d , Mark Rodgers a , Robert W. Bradsher Jr. c and L. Joseph Wheat a a MiraVista Diagnostics, Indianapolis, Indiana, USA b Indiana University School of Medicine and Roudebush Veterans' Administration Medical Center, Pulmonary Critical Care Medicine, Indianapolis, Indiana, USA c Division of Infectious Diseases, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA d Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky, Lexington, Kentucky, USA ABSTRACT The second-generation MVista Blastomyces antigen enzyme immunoassay was not quantitative; therefore, specimens obtained previously were tested in the same assay as new specimens to assess the change in antigen levels. Furthermore, the sensitivity in serum had not been fully evaluated. The purpose of this study was to evaluate a quantitative Blastomyces antigen assay and detection of antigen in serum. Calibrators containing known concentrations of Blastomyces galactomannan were used to quantify antigen in urine and serum from patients with proven blastomycosis and from controls. Paired current and previously obtained urine specimens were tested to determine if quantification eliminated the need for concurrent testing to assess change in antigen. Pretreatment of serum with EDTA at 104°C was evaluated to determine if dissociation of immune complexes improved detection of antigenemia. Antigenuria was detected in 89.9% of patients with culture- or histopathology-proven blastomycosis. Specificity was 99.0% in patients with nonfungal infections and healthy subjects, but cross-reactions occurred in 95.6% of patients with histoplasmosis. Change in antigen level categorized as increase, no change, or decrease based on antigen units determined in the same assay agreed closely with the category of change in ng/ml determined from different assays. Pretreatment increased the sensitivity of detection of antigenemia from 35.7% to 57.1%. Quantification eliminated the need for concurrent testing of current and previously obtained specimens for assessment of changes in antigen concentration. Pretreatment increased the sensitivity for detection of antigenemia. Differentiation of histoplasmosis and blastomycosis is not possible by antigen detection.

Journal

Clinical and Vaccine ImmunologyAmerican Society For Microbiology

Published: Jan 1, 2012

References