Keywords
Aspergillosis • Aspergillus fumigates • Diagnostics • ELISA •
Galactomannan antigen • Lungs • Respiratory tract1 Introduction
A delay in the diagnosis of fungal infections is a
consequence of unspecific clinical symptoms and
low sensitivity and specificity of the available
diagnostic tests (Haddad et al. 2015 ). Invasive
aspergillosis (IA) is an acute, most often fatal,
rapidly progressing infection in immunodeficient
patients. It usually prevails in the respiratory
tract, but may spread to other tissues and organs
(Kousha et al. 2011 ).Aspergillus fumigatesis
responsible for most infections; other species
less frequently lead to pulmonary aspergillosis
(Chabi et al. 2015 ; Maturu and Agarwal 2015 ).
Risk factors for invasive aspergillosis include
prolonged neutropenia (<500 cellsmm^3 for
10 days), transplantation (highest risk for lung
transplants and hematopoietic stem cell trans-
plantation), prolonged (>3 weeks) high-dose
corticosteroid therapy, hematological malig-
nancy (higher risk in leukemia), chemotherapy,
advanced acquired immune deficiency syndrome
(AIDS), and chronic granulomatous disease
(Kousha et al. 2011 ).
Standard diagnostics of aspergillosis include
CT scans, biopsies, microscopic imaging, and
cultures from tissue specimens (samples of ster-
ile body fluids and tissue sections) (Santos
et al. 2015 ). Serological tests, such as the
ELISA assay, often used to detect the
components of the fungal cell wall, are fre-
quently performed as a complementary diagnos-
tic test (Haddad et al. 2015 ). They detect
galactomannan, the main component of the
Aspergillus spp. cell wall, released during
hypha growth. This antigen may be detected in
both serum and bronchoalveolar lavage fluid
(BALF). However, BALF is more sensitive and
specific than the serum (Haddad et al. 2015 ;
Kousha et al. 2011 ; Wheat and Walsh 2008 ).
False negative/positive results are still a problem
(Marr et al. 2005 ; Singh et al. 2004 ). Therefore, it
is crucial to thoroughly check the patient’s medi-
cal history and monitor their condition to be able
to assess whether the results are false or not.
Molecular diagnostics consisting of BALF
and serum analyses by PCR is an alternative
way of diagnosing invasive pulmonary aspergil-
losis. Detection in serum is more sensitive and
specific (100 % and 65–92 %, respectively) than
in BALF (67–100 % and 55–95 %, respectively)
(Halliday et al. 2006 ; Hizel et al. 2004 ). How-
ever, the results may be false positive, as there
always is risk of inhaling fungal spores. Further-
more, molecular diagnostics do not differentiate
between colonization and infection.
Standard diagnostics of fungal infections
includes clinical observation and laboratory
tests. The definition of fungal infection was
published by the European Organization for
Research and Treatment of Cancer/Invasive Fun-
gal Infections Cooperative Croup and the
National Institute of Allergy and Infectious
Diseases Mycoses Study Group (EORTC/MSG)
in 2002. It has been introduced to simplify the
identification of similar patients for clinical trials
and epidemiological studies (de Pauw
et al. 2008 ; Ascioglu et al. 2002 ).
According to EORTC/MSG guidelines, there
are three levels of probability of invasive fungal
infections: proven, probable, and possible. The
diagnosis of a possible fungal infection is based
only on clinical symptoms and risk factors in a
patient. Probable and proven infections are addi-
tionally classified according to a positive sample
culture result and/or the detection of antigen in
blood serum (Haddad et al. 2015 ). Figure 1
presents the details of the classification of inva-
sive infections according to EORTC/MSG
guidelines.28 E. Swoboda-Kopec ́et al.