Long-term stability at -20 °C of Aspergillus galactomannan in serum and bronchoalveolar lavage specimens.
Research to develop and validate novel methods for diagnosis of aspergillosis based on detection of galactomannan requires the use of clinical specimens that have been stored frozen. Data indicating that galactomannan remains stable when frozen are scant. The objective of this study was to determine the stability of galactomannan in clinical specimens stored at -20 °C that were positive in the Platelia Aspergillus enzyme immunoassay when initially tested. Prospective real-time testing of serum and bronchoalveolar lavage (BAL) fluid pools from positive and negative patient specimens showed no decline in galactomannan index (GMI) over 11 months at -20 °C and no development of positive reactions in the negative-control pool. Retrospective testing of positive specimens that had been stored at -20 °C for 5 years showed that 28 of 30 serum (n = 15) or BAL (n = 15) specimens remained positive. These findings support the use of frozen serum or BAL specimens stored for at least 5 years in evaluation of diagnostic tests based on detection of galactomannan.
MiraVista Diagnostics, Indianapolis, Indianapolis, USA jwheat@miravistalabs.com.
L Joseph
LJ
Wheat
University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
M Hong
MH
Nguyen
Duke University Medical Center, Durham, North Carolina, USA.
Barbara D
BD
Alexander
The University of Manchester, Manchester, England.
David
D
Denning
Alpert Medical School of Brown University, Providence, Rhode Island, USA.
Angela M
AM
Caliendo
Emory University School of Medicine, Atlanta, Georgia, USA.
G Marshall
GM
Lyon
Harvard University & Brigham & Women's Hospital, Boston, Massachusetts, USA.
Lindsey R
LR
Baden
Harvard University & Brigham & Women's Hospital, Boston, Massachusetts, USA.
Francisco M
FM
Marty
University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Cornelius
C
Clancy
MiraVista Diagnostics, Indianapolis, Indianapolis, USA.
Emily
E
Kirsch
MiraVista Diagnostics, Indianapolis, Indianapolis, USA.
Pamela
P
Noth
University of Florida, Gainesville, Florida, USA.
John
J
Witt
University of Florida, Gainesville, Florida, USA.
Michele
M
Sugrue
University of Florida, Gainesville, Florida, USA.
John R
JR
Wingard
D001228:Aspergillosis / Q000175:diagnosis*; D001230:Aspergillus / Q000302:isolation & purification*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D005615:Freezing; D005690:Galactose / Q000031:analogs & derivatives; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D008351:Mannans / Q000032:analysis*; D044967:Serum / Q000737:chemistry*; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors
D008351:Mannans; C012990:galactomannan; D005690:Galactose