Performance of lateral flow device and galactomannan for the detection of Aspergillus species in bronchoalveolar fluid of patients at risk for invasive pulmonary aspergillosis

Point-of-care testing for viral-associated pulmonary aspergillosis

INTRODUCTION

Over the last years, severe respiratory viral infections, particularly those caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the influenza virus, have emerged as risk factor for viral-associated pulmonary aspergillosis (VAPA) among critically ill patients. Delays in diagnosis of VAPA are associated with increased mortality. Point-of-care-tests may play an important role in earlier diagnosis of VAPA and thus improve patient outcomes.

AREAS COVERED

The following review will give an update on point-of-care tests for VAPA, analyzing performances in respiratory and blood specimens.

EXPERT OPINION

Point-of-care tests have emerged, and particularly the IMMY Aspergillus galactomannan lateral flow assay (LFA) shows performances comparable to the galactomannan ELISA for diagnosis of VAPA. Notably, nearly all evaluations of POC tests for VAPA have been performed in COVID-19 patients, with very limited data in influenza patients. For early diagnosis of COVID associated pulmonary aspergillosis (CAPA), the LFA has shown promising performances in respiratory samples, particularly in bronchoalveolar lavage fluid, and may thereby help in improving patient outcomes. In contrast, serum LFA testing may not be useful for early diagnosis of disease, except in cases with invasive tracheobronchial aspergillosis.

Diagnosis of invasive pulmonary aspergillosis by lateral flow assay of galactomannan in bronchoalveolar lavage fluid: a meta-analysis of diagnostic performance

The performance of lateral flow assay (LFA) in diagnosing invasive pulmonary aspergillosis (IPA) has not been well demonstrated. To address this, we conducted a meta-analysis assessing the overall accuracy of LFA in diagnosing IPA using bronchoalveolar lavage fluid (BALF). Over a systematical search and assessment of bias risk, we calculated the pooled specificity, sensitivity, and area under the receiver operating curve (AUC) to assess the diagnostic performance. Our meta-analysis included 11 studies. The combined total sensitivity and specificity for diagnosing IPA were 0.78 (95% confidence interval (CI): 0.71, 0.83) and 0.87 (95% CI: 0.81, 0.91), respectively. The AUC was 0.86 (95% CI: 0.82, 0.89). Our results demonstrate that LFA using galactomannan in BALF exhibits high sensitivity and specificity for diagnosing IPA.

Implementation of Lateral Flow Assays for the Diagnosis of Invasive Aspergillosis in European Hospitals: A Survey from Belgium and a Literature Review of Test Performances in Different Patient Populations

OBJECTIVES

Diagnosis of invasive aspergillosis is based on a combination of criteria, of which the detection of Aspergillus galactomannan (GM) often is decisive. To date, the most commonly used method to determine GM is an enzyme-linked immune assay (EIA). But since a few years lateral flow assays (LFAs) were introduced, providing the possibility for rapid single sample testing. More and more LFAs are entering the market, but, although often being equated, all use their own antibodies, procedures and interpretation criteria. A recent European survey revealed that about 24-33% of laboratories implemented a lateral flow assay on-site.

METHODS

We conducted a survey at 81 Belgian hospital laboratories regarding the implementation of LFAs in their centre. In addition, we performed an extensive review of all publicly available studies on the performance of lateral flow assays to diagnose invasive aspergillosis.

RESULTS

Response rate to the survey was 69%. Of the 56 responding hospital laboratories, 6 (11%) used an LFA. The Soña Aspergillus galactomannan LFA (IMMY, Norman, Oklahoma, USA) was used in 4/6 centres, while two centres used the QuicGM (Dynamiker, Tianjin, China) and one centre used the FungiXpert Aspergillus Galactomannan Detection K-set LFA (Genobio [Era Biology Technology], Tianjin, China). One centre used 2 distinct LFAs. In 3/6 centres, the sample is sent to another lab for confirmation with GM-EIA when the LFA result is positive and in 2/6 when the LFA results is negative. In one centre, a confirmatory GM-EIA is always performed in house. In three centres the LFA result is used as a complete substitute for GM-EIA. Available LFA performance studies are very diverse and results vary in function of the study population and type of LFA. Apart from the IMMY and OLM LFA, only very limited performance data are available. From two out of three LFAs used in Belgium, no clinical performance studies are published in literature.

CONCLUSIONS

A large variety of LFAs are used in Belgian Hospitals, some of which no clinical validation studies are published. These results do likely have implications for other parts of Europe and for the rest of the world as well. Due to the variable performance of LFA tests and the limited validation data available, each laboratory must check the available performance information of the specific test considered for implementation. In addition, laboratories should perform an implementation verification study.

Aspergillosis: Emerging risk groups in critically ill patients

Information on invasive aspergillosis (IA) and other invasive filamentous fungal infections is limited in non-neutropenic patients admitted to the intensive care unit (ICU) and presenting with no classic IA risk factors. This review is based on the critical appraisal of relevant literature, on the authors' own experience and on discussions that took place at a consensus conference. It aims to review risk factors favoring aspergillosis in ICU patients, with a special emphasis on often overlooked or neglected conditions. In the ICU patients, corticosteroid use to treat underlying conditions such as chronic obstructive pulmonary disease (COPD), sepsis, or severe COVID-19, represents a cardinal risk factor for IA. Important additional host risk factors are COPD, decompensated cirrhosis, liver failure, and severe viral pneumonia (influenza, COVID-19). Clinical observations indicate that patients admitted to the ICU because of sepsis or acute respiratory distress syndrome are more likely to develop probable or proven IA, suggesting that sepsis could also be a possible direct risk factor for IA, as could small molecule inhibitors used in oncology. There are no recommendations for prophylaxis in ICU patients; posaconazole mold-active primary prophylaxis is used in some centers according to guidelines for other patient populations and IA treatment in critically ill patients is basically the same as in other patient populations. A combined evaluation of clinical signs and imaging, classical biomarkers such as the GM assay, and fungal cultures examination, remain the best option to assess response to treatment.

LAY SUMMARY

The use of corticosteroids and the presence of co-morbidities such as chronic obstructive pulmonary disease, acute or chronic advanced liver disease, or severe viral pneumonia caused by influenza or Covid-19, may increase the risk of invasive aspergillosis in intensive care unit patients.

Future challenges and chances in the diagnosis and management of invasive mould infections in cancer patients

Diagnosis, treatment, and management of invasive mould infections (IMI) are challenged by several risk factors, including local epidemiological characteristics, the emergence of fungal resistance and the innate resistance of emerging pathogens, the use of new immunosuppressants, as well as off-target effects of new oncological drugs. The presence of specific host genetic variants and the patient's immune system status may also influence the establishment of an IMI and the outcome of its therapy. Immunological components can thus be expected to play a pivotal role not only in the risk assessment and diagnosis, but also in the treatment of IMI. Cytokines could improve the reliability of an invasive aspergillosis diagnosis by serving as biomarkers as do serological and molecular assays, since they can be easily measured, and the turnaround time is short. The use of immunological markers in the assessment of treatment response could be helpful to reduce overtreatment in high risk patients and allow prompt escalation of antifungal treatment. Mould-active prophylaxis could be better targeted to individual host needs, leading to a targeted prophylaxis in patients with known immunological profiles associated with high susceptibility for IMI, in particular invasive aspergillosis. The alteration of cellular antifungal immune response through oncological drugs and immunosuppressants heavily influences the outcome and may be even more important than the choice of the antifungal treatment. There is a need for the development of new antifungal strategies, including individualized approaches for prevention and treatment of IMI that consider genetic traits of the patients.

Lay Abstract

Anticancer and immunosuppressive drugs may alter the ability of the immune system to fight invasive mould infections and may be more important than the choice of the antifungal treatment. Individualized approaches for prevention and treatment of invasive mold infections are needed.

Invasive aspergillosis in solid organ transplant patients: diagnosis, prophylaxis, treatment, and assessment of response

BACKGROUND

Invasive aspergillosis (IA) is a rare complication in solid organ transplant (SOT) recipients. Although IA has significant implications on graft and patient survival, data on diagnosis and management of this infection in SOT recipients are still limited.

METHODS

Discussion of current practices and limitations in the diagnosis, prophylaxis, and treatment of IA and proposal of means of assessing treatment response in SOT recipients.

RESULTS

Liver, lung, heart or kidney transplant recipients have common as well as different risk factors to the development of IA, thus each category needs a separate evaluation. Diagnosis of IA in SOT recipients requires a high degree of awareness, because established diagnostic tools may not provide the same sensitivity and specificity observed in the neutropenic population. IA treatment relies primarily on mold-active triazoles, but potential interactions with immunosuppressants and other concomitant therapies need special attention.

CONCLUSIONS

Criteria to assess response have not been sufficiently evaluated in the SOT population and CT lesion dynamics, and serologic markers may be influenced by the underlying disease and type and severity of immunosuppression. There is a need for well-orchestrated efforts to study IA diagnosis and management in SOT recipients and to develop comprehensive guidelines for this population.

Evaluation of two lateral flow assays in BAL fluids for the detection of invasive pulmonary aspergillosis: A retrospective two-centre study

BACKGROUND

Commonly, the application of radiological and clinical criteria and the determination of galactomannan (GM) in respiratory samples are used as a diagnostic tool for the detection of invasive pulmonary aspergillosis (IPA).

MATERIALS/METHODS

In this study, two lateral flow assays, OLM Aspergillus lateral flow device (LFD) and IMMY sōna Aspergillus Galactomannan lateral flow assay (LFA), were evaluated at two tertiary hospitals in Germany. A total of 200 bronchoalveolar lavage (BAL) samples from patients with suspicion of IPA were analysed retrospectively. LFD and LFA were evaluated against four different criteria: Blot, EORTC/MSG, Schauwvlieghe and extended Blot criteria and additionally against GM.

RESULTS

The evaluation of four algorithms for the diagnosis of IPA showed that there exist good diagnostic tools to rule out an IPA even before results of Aspergillus culture are available. Sensitivities and negative predictive values are generally higher for the LFA than for the LFD in all four criteria. Specificity and positive predictive values varied depending on the classification criteria. The total agreement between the GM and the LFA cube reader (cut-off = 1) was 84%. The correlation between the GM and LFA was calculated with r = 0.8.

CONCLUSION

The here presented data indicate that a negative LFA result in BAL fluid can reliable rule out an IPA in a heterogeneous group of ICU patients based on the original Blot criteria. LFA seems to be a promising immunochromatographic test exhibiting a good agreement with positive GM values.

Point-of-care diagnostics for invasive aspergillosis: nearing the finish line

INTRODUCTION

The spectrum of disease caused by Aspergillus spp. is dependent on the immune system of the host, with invasive aspergillosis (IA) its most severe manifestation. Early and reliable diagnosis of Aspergillus disease is important to decrease associated morbidity and mortality from IA.

AREAS COVERED

The following review searched Pub Med for literature published since 2007 and will give an update on the current point-of-care diagnostic strategies for the diagnosis of IA, discuss needed areas of improvement for these tests, and future directions.

EXPERT OPINION

Several new diagnostic tests for IA - including point-of-care tests - are now available to complement conventional galactomannan (GM) testing. In particular, the Aspergillus-specific Lateral Flow Device (LFD) test and the sōna Aspergillus GM Lateral Flow Assay (LFA) are promising for the diagnosis of IA in patients with hematologic malignancy, although further evaluation in the non-hematology setting is needed. In addition, a true point-of-care test, particularly for easily obtained specimens like serum or urine that can be done at the bedside or in the Clinic in a matter of minutes is needed, such as the lateral flow dipstick test, which is under current evaluation. Lastly, improved diagnostic algorithms to diagnose IA in non-neutropenic patients is needed.

Aspergillus fumigatus and Aspergillosis in 2019

Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.

Clinical application of Aspergillus lateral flow device in bronchoalveolar lavage fluid of patients with classic risk factors for invasive pulmonary aspergillosis

BACKGROUND

The diagnosis of invasive pulmonary aspergillosis (IPA) remains challenging. We evaluated the performance characteristics of a newly formatted Aspergillus lateral flow test, AspLFD, in bronchoalveolar lavage (BAL) fluid from patients with classic risk factors for IPA.

METHODS

Prospectively banked BAL samples from 14 patients with proven or probable IPA defined by EORTC/MSG criteria and 28 BAL samples from age-matched high-risk patients without IPA were tested with AspLFD according to manufacturer's directions. Results were read by two independent observers, and test performance was calculated.

RESULTS

Age, gender and underlying risk factors, except for neutropenia and haematological malignancy, were similar between IPA cases and controls. Seven patients (50%) in the IPA group received a mould-active agent within 5 days prior to bronchoscopy compared with only three patients (11%) in the control group, P = .004. Of 14 patients with proven/probable IPA, AspLFD was positive in 3 and negative in 9; two tests yielded invalid results. All 28 control patients had a negative AspLFD test. AspLFD showed low sensitivity (25%, 95% CI: 5.5% to 57.2%), but high specificity (100%. (95% CI: 87.7% to 100%).

CONCLUSIONS

A positive AspLFD test in BAL fluid of patients with classic risk factors for IPA could be useful to support the diagnosis of proven/probable IPA because of its high specificity. However, as a stand-alone test for IPA, the use of AspLFD is limited by low sensitivity.

Invasive mould infections in solid organ transplant patients: modifiers and indicators of disease and treatment response

PURPOSE

Invasive mould infections, in particular invasive aspergillosis (IA), are comparatively frequent complications of immunosuppression in patients undergoing solid organ transplantation (SOT). Guidelines provide recommendations as to the procedures to be carried out to diagnose and treat IA, but only limited advice for SOT recipients.

METHODS

Literature review and expert consensus summarising the existing evidence related to prophylaxis, diagnosis, treatment and assessment of response to IA and infections by Mucorales in SOT patients RESULTS: Response to therapy should be assessed early and at regular intervals. No indications of improvement should lead to a prompt change of the antifungal treatment, to account for possible infections by Mucorales or other moulds such as Scedosporium. Imaging techniques, especially CT scan and possibly angiography carried out at regular intervals during early and long-term follow-up and coupled with a careful clinical diagnostic workout, should be evaluated as diagnostic tools and outcome predictors, and standardised to improve therapy monitoring. The role of biomarkers such as the galactomannan test and PCR, as well as selected inflammation parameters, has not yet been definitively assessed in the SOT population and needs to be studied further. The therapeutic workup should consider a reduction of immunosuppressive therapy.

CONCLUSIONS

The role of immunosuppression and immune tolerance mechanisms in the response to invasive fungal infection treatment is an important factor in the SOT population and should not be underestimated. The choice of the antifungal should consider not only their toxicity but also their effects on the immune system, two features that are intertwined.

Evaluation of a Novel Aspergillus Antigen Enzyme-Linked Immunosorbent Assay

Invasive aspergillosis (IA) is a life-threatening infection that mainly occurs in immunocompromised patients. Here, we compared the novel Aspergillus-specific galactomannoprotein (GP) enzyme-linked immunosorbent assay (ELISA) (Euroimmun Medizinische Labordiagnostika AG) to the established Platelia Aspergillus galactomannan (GM) ELISA (Bio-Rad Laboratories) for the detection of IA.

Invasive aspergillosis (IA) is a life-threatening infection that mainly occurs in immunocompromised patients. Here, we compared the novel Aspergillus-specific galactomannoprotein (GP) enzyme-linked immunosorbent assay (ELISA) (Euroimmun Medizinische Labordiagnostika AG) to the established Platelia Aspergillus galactomannan (GM) ELISA (Bio-Rad Laboratories) for the detection of IA. A total of 267 serum samples from 45 cases of proven and 4 episodes of probable IA (according to European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group [EORTC/MSG] criteria) and 156 sera from patients without evidence of IA were tested. Pearson’s correlation statistics, as well as sensitivity and specificity, were calculated using manufacturer-recommended (GM) or optimized (GP) cutoff levels. Aspergillus fumigatus was found in 88% of culture-positive infections. When we analyzed all 423 serum samples, GM and GP tests correlated strongly (r = 0.82, P < 0.0001). Among proven IA cases using samples obtained as closely as possible to the day of proven diagnosis, the sensitivity for both tests was 40%. All cases of probable IA (defined by positive GM testing) were also GP positive. Concordant results of the two ELISAs were obtained in 43 of 49 samples (88%). Extending measurements to all sera available in the time frame of 7 days prior to 7 days after the day of proven diagnosis, 47% and 56% of the cases were detected by the GM and GP tests, respectively. Specificity was 99% for GM and 96% for GP testing. For the diagnosis of IA, sensitivity and specificity of the novel GP ELISA are similar to those of the Platelia GM ELISA. The low sensitivities of both tests underline the need for serial testing in patients at risk for IA.

Galactomannan detection in broncho-alveolar lavage fluid for invasive aspergillosis in immunocompromised patients

BACKGROUND

Invasive aspergillosis (IA) is a life-threatening opportunistic mycosis that occurs in some people with a compromised immune system. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) rapidly gained widespread acceptance as part of the diagnostic work-up of a patient suspected of IA. Due to its non-invasive nature, it can be used as a routine screening test. The ELISA can also be performed on bronchoalveolar lavage (BAL), allowing sampling of the immediate vicinity of the infection. The invasive nature of acquiring BAL, however, changes the role of the galactomannan test significantly, for example by precluding its use as a routine screening test.

OBJECTIVES

To assess the diagnostic accuracy of galactomannan detection in BAL for the diagnosis of IA in people who are immunocompromised, at different cut-off values for test positivity, in accordance with the Cochrane Diagnostic Test Accuracy Handbook.

SEARCH METHODS

We searched three bibliographic databases including MEDLINE on 9 September 2016 for aspergillosis and galactomannan as text words and subject headings where appropriate. We checked reference lists of included studies for additional studies.

SELECTION CRITERIA

We included cohort studies that examined the accuracy of BAL galactomannan for the diagnosis of IA in immunocompromised patients if they used the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) classification as reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors assessed study quality and extracted data. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used for quality assessment.

MAIN RESULTS

We included 17 studies in our review. All studies except one had a high risk of bias in two or more domains. The diagnostic performance of an optical density index (ODI) of 0.5 as cut-off value was reported in 12 studies (with 1123 patients). The estimated sensitivity was 0.88 (95% confidence interval (CI) 0.75 to 1.00) and specificity 0.81 (95% CI 0.71 to 0.91). The performance of an ODI of 1.0 as cut-off value could be determined in 11 studies (with 648 patients). The sensitivity was 0.78 (95% CI 0.61 to 0.95) and specificity 0.93 (95% CI 0.87 to 0.98). At a cut-off ODI of 1.5 or higher, the heterogeneity in specificity decreased significantly and was invariably >90%.

AUTHORS' CONCLUSIONS

The optimal cut-off value depends on the local incidence and clinical pathway. At a prevalence of 12% a hypothetical population of 1000 patients will consist of 120 patients with IA. At a cut-off value of 0.5 14 patients with IA will be missed and there will be 167 patients incorrectly diagnosed with IA. If we use the test at a cut-off value of 1.0, we will miss 26 patients with IA. And there will be 62 patients incorrectly diagnosed with invasive aspergillosis. The populations and results were very heterogeneous. Therefore, interpretation and extrapolation of these results has to be performed with caution. A test result of 1.5 ODI or higher appears a strong indicator of IA.

Diagnostic work up to assess early response indicators in invasive pulmonary aspergillosis in adult patients with haematologic malignancies

In immunocompromised patients with acute leukaemia as well as in allogeneic hematopoietic stem cell transplant patients, pulmonary lesions are commonly seen. Existing guidelines provide useful algorithms for diagnostic procedures and treatment options, but they do not give recommendations on how to evaluate early success or failure and if or when it is best to change therapy. Here, we review the diagnostic techniques currently used in association with clinical findings and propose an approach using a combination of computer tomography, clinical and all available biomarkers and inflammation parameters, especially those positive at baseline, to assess early response in invasive pulmonary aspergillosis. Computed tomography scans should be carried out at regular intervals during early and long-term follow-up. Imaging on day seven, or even earlier in clinically unstable patients, combined with an additional testing of biomarkers and inflammatory markers in between, is needed for a reliable assessment at day 14. If no improvement is seen after 2 weeks of therapy or the clinical condition is deteriorating, a change of antifungal therapy should be considered. Alleged breakthrough infections or treatment failure should undergo early diagnostic workup, including tissue biopsies when possible, to retrieve fungal cultures for resistance testing.

The performance of galactomannan in combination with 1,3-β-D-glucan or aspergillus-lateral flow device for the diagnosis of invasive aspergillosis: Evidences from 13 studies

Galactomannan (GM), 1,3-β-D-glucan (BDG) and aspergillus-lateral flow device (LFD) are recognized as diagnostic tools for invasive aspergillosis (IA). The combined performance of these assays, however, is inconsistent in various studies. We undertook a meta-analysis of 13 studies involving 1513 patients to evaluate the utility of GM in combination with BDG or LFD for diagnosing IA. The pooled SEN, SPE, PLR, NLR and diagnostic odds ratio (DOR) were calculated and constructed to summarize the overall combined performance. Combining both positive results of GM and BDG assays leaded to the pooled SEN 0.49 (95%CI 0.27-0.72), SPE 0.98 (95%CI 0.94-1.00), PLR 31.68 (95%CI 5.36-187.37), NLR 0.52 (95%CI 0.32-0.84) and DOR 61.23 (95%CI 6.96-538.90). Comparing with GM and BDG assays, both positive results of GM and LFD leaded to high SEN, similar SPE, low PLR and NLR. At least one positive result of GM or LFD conferred great SEN 0.93 and low NLR 0.08. Both positive results of GM and BDG or LFD assay were in favor of confirming the existence of IA. And both negative results of GM and LFD were beneficial to rule out IA. Further studies with sufficient sample size should focus on the diagnostic performance and cost-effectiveness of these combined tests in clinical setting.

The evolving landscape of new diagnostic tests for invasive aspergillosis in hematology patients: strengths and weaknesses

PURPOSE OF REVIEW

The diagnosis of invasive aspergillosis in hematologic patients is a complex composite of clinical preconditions and features, imaging findings, biomarker combinations from appropriate clinical samples and microbiological and/or histological findings.

RECENT FINDINGS

Recent developments in the evolving landscape of diagnostic tests for invasive aspergillosis in adult hematology patients are highlighted.

SUMMARY

Novel approaches and tools are currently under development. Focusing optimized diagnostic performance, in particular the combination of biomarkers from appropriate clinical samples, improved diagnostic performance distinctly.

Clinical evaluation of the newly formatted lateral-flow device for invasive pulmonary aspergillosis

The study evaluated the newly formatted Aspergillus-specific lateral-flow-device (LFD), and compared its performance to the original prototype "old" LFD test using BALF samples from 28 patients (14 patients with probable/proven invasive pulmonary aspergillosis [IPA] and 14 patients with no evidence for IPA). A total of 10/14 (71%) of BALF samples from patients with probable/proven IPA resulted positive with the new LFD, including 8/9 with true-positive and 2/5 with false-negative results with the old LFD. All 14 samples from patients without IPA resulted negative with the new LFD; specificity of the new LFD was significantly improved compared to the old LFD.

Testing the performance of a prototype lateral flow device using bronchoalveolar lavage fluid for the diagnosis of invasive pulmonary aspergillosis in high-risk patients

The diagnosis of invasive pulmonary aspergillosis (IPA) increasingly relies on non-culture-based biomarkers in bronchoalveolar lavage (BAL) fluid. The Aspergillus lateral flow device (LFD) is a rapid immunoassay that uses a novel Aspergillus monoclonal antibody to gain specificity. The objective of the study is to compare specificity and sensitivity of the prototype LFD and the galactomannan (GM) enzyme immunoassay in BAL fluid in high-risk patients. A total of 114 BAL samples from 106 patients at high risk for IPA were studied: 8 patients had proven/probable IPA, 16 had possible IPA and 82 did not have IPA. In patients with proven/probable IPA, specificity of LFD was 94% and GM was 89%; sensitivity of LFD was 38% and GM was 75%. Negative predictive value (NPV) for LFD was 94% and for GM was 98%; positive predictive value (PPV) was 38% for both tests. The use of anti-mould prophylaxis did not affect specificity but resulted in decreased NPV of both LFD and GM. Union and intersection analysis showed no improvement in the performance by using both tests. Among patients at risk for IPA, the diagnostic performance of LFD and GM in BAL fluid appears comparable; specificity is high, but sensitivity of both LFD and GM is poor.

Lateral Flow Assays for the Diagnosis of Invasive Aspergillosis: Current Status

PURPOSE OF REVIEW

Diagnosis during early stages of invasive aspergillosis (IA) and targeted antifungal treatment has the potential to improve survival significantly. Despite advances in the diagnostic arsenal, invasive mold infections remain difficult to diagnose-especially at early stages before typical radiological signs develop. Varying availability and time-to-results are important limitations of current approved biomarkers and molecular assays for diagnosis of IA. Here, we will give an update on the Aspergillus-specific lateral-flow device (LFD) test. We further review promising findings on feasibility of point-of-care (POC) detection of urinary excreted fungal galactomannan-like antigens.

RECENT FINDINGS

POC LFD assays for detection of Aspergillus antigens are currently in development. The Aspergillus-specific LFD test, which is based on the JF5 antibody (Ab), detects an extracellular glycoprotein antigen secreted during active growth of Aspergillus spp. The test has shown promising results in various studies. In addition, a monoclonal Ab476-based LFD for POC detection of urinary excreted fungal galactomannan-like antigens has been developed but needs further validation.

SUMMARY

Important advances have been made in the development of LFD assays for IA. Most promising is the Aspergillus-specific LFD test; commercial availability is still pending, however. The search for reliable POC tests for other molds, including mucorales, continues.

Pediatric Invasive Aspergillosis

Invasive aspergillosis (IA) is a disease of increasing importance in pediatrics due to growth of the immunocompromised populations at risk and improvements in long-term survival for many of these groups. While general principles of diagnosis and therapy apply similarly across the age spectrum, there are unique considerations for clinicians who care for children and adolescents with IA. This review will highlight important differences in the epidemiology, clinical manifestations, diagnosis, and therapy of pediatric IA.

Point of Care Testing for the Diagnosis of Fungal Infections: Are We There Yet?

Diagnostic tools for invasive fungal infections have continuously improved within the last decades. Nowadays, cultural methods, antigen testing, and molecular tests, such as polymerase chain reaction, are widely used. These methods, however, are accompanied with different limitations as various availability, various turnaround time or high costs. A new generation of point-of-care test has shown promising results in various studies and may overcome some of these limitations. We therefore reviewed the literature for the most promising new point-of-care tests for invasive aspergillosis (Aspergillus-specific lateral-flow device test, Aspergillus proximity ligation antigen assay), cryptococcosis (cryptococcal lateral-flow assay), and for histoplasmosis (loop-mediated isothermal amplification assay).