Prospective Aspergillus galactomannan antigen testing in pediatric hematopoietic stem cell transplant recipients.
BACKGROUND
The galactomannan (GM) assay is an approved noninvasive test for detection of invasive aspergillosis (IA) that has been validated in adult patients with hematologic malignancies who are undergoing bone marrow transplantation. There have been few studies with this assay in pediatric patients, but early reports suggest that there may be differences in the performance such that false-positive GM tests in pediatric patients are more common than in adult patients.


METHODS
We performed a prospective study in pediatric hematopoietic stem cell transplant recipients with twice-weekly sampling for GM detection during the highest risk periods of neutropenia and graft-versus-host disease. We analyzed 826 serum samples from 64 patients, including 15 serum samples from one patient diagnosed with probable IA according to defined criteria.


RESULTS
Twenty of 811 samples tested positive on repeat testing (specificity, 97.5%; 95% CI: 96.2-98.4%) including samples from 8 of 63 patients without clinical evidence of IA according to study criteria (specificity, 87.3%; 95% CI: 76.9-93.4%). Eleven patients received piperacillin/tazobactam therapy, and 4 of the 11 patients had a positive assay result coinciding with the dates of piperacillin/tazobactam administration. When samples from these patients were excluded, specificity increased to 98.4% (95% CI: 97.2-99.1%) by sample and to 91.5% (95% CI: 81.6-96.3%) by patient.


CONCLUSIONS
The GM assay holds promise for early, noninvasive diagnosis of IA in high-risk children and false-positive results were not common or unexplainable. This study supports further validation of this assay in a large-scale, pediatric-dedicated format.
Steinbach
William J
WJ
Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA. stein022@mc.duke.edu
Addison
Rachel M
RM
McLaughlin
Lisa
L
Gerrald
Quincy
Q
Martin
Paul L
PL
Driscoll
Timothy
T
Bentsen
Christopher
C
Perfect
John R
JR
Alexander
Barbara D
BD
D000946:Antigens, Fungal / Q000276:immunology*; D001228:Aspergillosis / Q000175:diagnosis; D001230:Aspergillus / Q000302:isolation & purification*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005690:Galactose / Q000031:analogs & derivatives; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008351:Mannans / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D000946:Antigens, Fungal; D008351:Mannans; C012990:galactomannan; D005690:Galactose