An evaluation of the performance of the Dynamiker® Fungus (1-3)-β-D-Glucan Assay to assist in the diagnosis of Pneumocystis pneumonia

Dynamic changes in serum (1-3)-β-D-glucan caused by intravenous immunoglobulin infusion: A prospective study

PURPOSE

The purpose of this study was to investigate the dynamic changes in serum (1-3)-β-D-glucan (BDG) caused by intravenous immunoglobulins (IVIG) infusion in adults.

METHODS

This study included patients who received IVIG infusion from October 2021 to October 2022 during hospitalization. We randomly examined two IVIG samples for every patient. Serum samples were collected at nine time points: before (Tpre), immediately (T1-0), 6h (T1-1) and 12h (T1-2) later on the first day; immediately (T2-0) and six hours later (T2-1) on the second day during IVIG infusion, and within three days after IVIG infusion (Ta1, Ta2, and Ta3, respectively). The Friedman test was used for statistical analysis.

RESULTS

A total of 159 serum BDG from 19 patients were included in the analysis. The BDG content of IVIG ranged from 249 pg/ml to 4812 pg/ml. Patients had significantly elevated serum BDG on T1-0 (176 (113, 291) pg/ml, p = 0.002) and Ta1 (310 (199, 470) pg/ml, p < 0.001), compared with Tpre (41 (38, 65) pg/ml). The increments of serum BDG (ΔBDG) were associated with BDG concentration of IVIG (Spearman r = 0.59, p = 0.02). Individuals with abnormal renal function indexes showed higher serum ΔBDG values at Ta1 (403 (207, 484) pg/ml) than patients with normal renal function (172 (85, 316) pg/ml, p = 0.036).

CONCLUSION

Patients who received IVIG had significantly higher serum BDG values. Elevated BDG levels correlate with BDG content of IVIG and abnormal renal function indexes.

Evaluation of the Performance of the Dynamiker Fungus (1-3)-β-D-Glucan and Fungitell Assay for Diagnosis of Candidemia: Need for New Cut-off Development and Test Validation

(1-3)-Beta-D Glucan (BDG) detection has shown to be a highly effective tool to diagnose invasive fungal infections. Therefore, this study aimed to compare clinical characteristics of the Fungitell (FA) and Dynamiker Fungus (1-3)-β-D-Glucan assay (DFA) for the diagnosis of candidemia. Using DFA and FA, the BDG levels of 57 serum samples from case and control groups were determined. The kappa coefficient (κ) and Spearman's rank correlation (rs) were used to examine the consistency of assays on a quantitative and qualitative level, respectively. The sensitivity, specificity, and accuracy were 94.6 %, 65.0 %, and 87.7% for DFA, and 94.6 %, 75.0 %, and 89.4 % for FA, respectively. The performance of the DFA for the diagnosis of candidemia was highly consistent with that of the FA, both quantitatively (rs: 0.9) and qualitatively (kappa = 0.78). Collectively, the DFA assay performed excellently in comparison to the FA for the diagnosis of candidemia.

Developments in Fungal Serology

Purpose of Review

The true incidence of fungal disease is hampered by conventionally poor diagnostic tests, limited access to advanced diagnostics, and limited surveillance. The availability of serological testing has been available for over two decades and generally underpins the modern diagnosis of the most common forms of fungal disease. This review will focus on technical developments of serological tests for the diagnosis of fungal disease, describing advances in clinical performance when available.

Recent Findings

Despite their longevity, technical, clinical, and performance limitations remain, and tests specific for fungal pathogens outside the main pathogens are lacking. The availability of LFA and automated systems, capable of running multiple different tests, represents significant developments, but clinical performance data is variable and limited.

Summary

Fungal serology has significantly advanced the diagnosis of the main fungal infections, with LFA availability increasing accessibility to testing. Combination testing has the potential to overcome performance limitations.

Diagnostic accuracy of the 1,3-beta-D-glucan test and lactate dehydrogenase for pneumocystis pneumonia in non-HIV patients

We evaluated the serum levels of (1–3)-beta-d-glucan (BG) and lactate dehydrogenase (LDH) as a tool to support pneumocystis pneumonia (PCP) diagnostic procedures in non-HIV patients. We retrospectively collected non-HIV (human immunodeficiency virus) patients presenting clinical features of PCP between April 1st, 2013, and December 31st, 2018. A total of 225 included patients were tested for Pneumocystis jirovecii by polymerase chain reaction (PCR) and methenamine silver staining. Based on different exclusion criteria, 179 cases were included in the BG group, and 196 cases were included in the LDH group. In each group, cases with positive immunofluorescence (IF) microscopy and PCR were considered proven PCP, while cases with only positive PCR were considered probable PCP. Fifty patients with negative IF and PCR results and proven to be non-PCP infection were chosen randomly as the control group. The cut-off levels of BG and LDH to distinguish non-PCP from probable PCP were 110 pg/mL and 296 U/L with 88% sensitivity and 86% specificity, and 66% sensitivity and 88% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven PCP were 285.8 pg/mL and 379 U/L with 92% sensitivity and 96% specificity, and 85% sensitivity and 77% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven/probable PCP were 144.1 pg/mL and 363 U/L with 90% sensitivity, 86% specificity and 80% sensitivity, 76% specificity respectively. BG and LDH are reliable indicators for detecting P. jirovecii infection in HIV-uninfected immunocompromised patients.

(1→3)-β-D-glucan testing for the detection of invasive fungal infections in immunocompromised or critically ill people

BACKGROUND

Invasive fungal infections (IFIs) are life-threatening opportunistic infections that occur in immunocompromised or critically ill people. Early detection and treatment of IFIs is essential to reduce morbidity and mortality in these populations. (1→3)-β-D-glucan (BDG) is a component of the fungal cell wall that can be detected in the serum of infected individuals. The serum BDG test is a way to quickly detect these infections and initiate treatment before they become life-threatening. Five different versions of the BDG test are commercially available: Fungitell, Glucatell, Wako, Fungitec-G, and Dynamiker Fungus.

OBJECTIVES

To compare the diagnostic accuracy of commercially available tests for serum BDG to detect selected invasive fungal infections (IFIs) among immunocompromised or critically ill people.

SEARCH METHODS

We searched MEDLINE (via Ovid) and Embase (via Ovid) up to 26 June 2019. We used SCOPUS to perform a forward and backward citation search of relevant articles. We placed no restriction on language or study design.

SELECTION CRITERIA

We included all references published on or after 1995, which is when the first commercial BDG assays became available. We considered published, peer-reviewed studies on the diagnostic test accuracy of BDG for diagnosis of fungal infections in immunocompromised people or people in intensive care that used the European Organization for Research and Treatment of Cancer (EORTC) criteria or equivalent as a reference standard. We considered all study designs (case-control, prospective consecutive cohort, and retrospective cohort studies). We excluded case studies and studies with fewer than ten participants. We also excluded animal and laboratory studies. We excluded meeting abstracts because they provided insufficient information.

DATA COLLECTION AND ANALYSIS

We followed the standard procedures outlined in the Cochrane Handbook for Diagnostic Test Accuracy Reviews. Two review authors independently screened studies, extracted data, and performed a quality assessment for each study. For each study, we created a 2 × 2 matrix and calculated sensitivity and specificity, as well as a 95% confidence interval (CI). We evaluated the quality of included studies using the Quality Assessment of Studies of Diagnostic Accuracy-Revised (QUADAS-2). We were unable to perform a meta-analysis due to considerable variation between studies, with the exception of Candida, so we have provided descriptive statistics such as receiver operating characteristics (ROCs) and forest plots by test brand to show variation in study results.

MAIN RESULTS

We included in the review 49 studies with a total of 6244 participants. About half of these studies (24/49; 49%) were conducted with people who had cancer or hematologic malignancies. Most studies (36/49; 73%) focused on the Fungitell BDG test. This was followed by Glucatell (5 studies; 10%), Wako (3 studies; 6%), Fungitec-G (3 studies; 6%), and Dynamiker (2 studies; 4%). About three-quarters of studies (79%) utilized either a prospective or a retrospective consecutive study design; the remainder used a case-control design. Based on the manufacturer's recommended cut-off levels for the Fungitell test, sensitivity ranged from 27% to 100%, and specificity from 0% to 100%. For the Glucatell assay, sensitivity ranged from 50% to 92%, and specificity ranged from 41% to 94%. Limited studies have used the Dynamiker, Wako, and Fungitec-G assays, but individual sensitivities and specificities ranged from 50% to 88%, and from 60% to 100%, respectively. Results show considerable differences between studies, even by manufacturer, which prevented a formal meta-analysis. Most studies (32/49; 65%) had no reported high risk of bias in any of the QUADAS-2 domains. The QUADAS-2 domains that had higher risk of bias included participant selection and flow and timing.

AUTHORS' CONCLUSIONS

We noted considerable heterogeneity between studies, and these differences precluded a formal meta-analysis. Because of wide variation in the results, it is not possible to estimate the diagnostic accuracy of the BDG test in specific settings. Future studies estimating the accuracy of BDG tests should be linked to the way the test is used in clinical practice and should clearly describe the sampling protocol and the relationship of time of testing to time of diagnosis.

Diagnostic accuracy of serum (1-3)-β-D-glucan for Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) can be a life-threatening opportunistic infection in immunocompromised hosts. The diagnosis can be challenging, often requiring semi-invasive respiratory sampling. The serum 1,3-β-D-glucan (BDG) assay has been proposed as a minimally invasive test for the presumptive diagnosis of PJP.

METHOD

We carried out a systematic review and meta-analysis using articles in the English language published between January 1960 and September 2019. We estimated the pooled sensitivity and specificity of BDG testing using a bivariate random effects approach and compared test performance in human immunodeficiency virus (HIV) and non-HIV subgroups with meta-regression. Data from the pooled sensitivity and specificity were transformed to generate pre- and post-test probability curves.

RESULTS

Twenty-three studies were included. The pooled sensitivity and specificity of serum BDG testing for PJP were 91% (95%CI 87-94%) and 79% (95%CI 72-84%) respectively. The sensitivity in patients with HIV was better than in patients without (94%, 95%CI 91-96%) versus 86% (95%CI 78-91%) (p 0.02), with comparable specificity (83%, 95%CI 69-92% versus 83%, 95%CI 72-90%) (p 0.10). A negative BDG was only associated with a low post-test probability of PJP (≤5%) when the pre-test probability was low to intermediate (≤20% in non-HIV and ≤50% in HIV).

CONCLUSIONS

Among patients with a higher likelihood of PJP, the pooled sensitivity of BDG is insufficient to exclude infection. Similarly, for most cases, the pooled specificity is inadequate to diagnose PJP. Understanding the performance of BDG in the population being investigated is therefore essential to optimal clinical decision-making.

A consensus document for the clinical management of invasive fungal diseases in pediatric patients with hematologic cancer and/or undergoing hematopoietic stem cell transplantation in Brazilian medical centers

In the present paper we summarize the suggestions of a multidisciplinary group including experts in pediatric oncology and infectious diseases who reviewed the medical literature to elaborate a consensus document (CD) for the diagnosis and clinical management of invasive fungal diseases (IFDs) in children with hematologic cancer and those who underwent hematopoietic stem-cell transplantation. All major multicenter studies designed to characterize the epidemiology of IFDs in children with cancer, as well as all randomized clinical trials addressing empirical and targeted antifungal therapy were reviewed. In the absence of randomized clinical trials, the best evidence available to support the recommendations were selected. Algorithms for early diagnosis and best clinical management of IFDs are also presented. This document summarizes practical recommendations that will certainly help pediatricians to best treat their patients suffering of invasive fungal diseases.

Non-culture based assays for the detection of fungal pathogens

Traditional, culture based methods for the diagnosis of fungal infections are still considered as gold standard, but they are time consuming and low sensitive. Therefore, in order to overcome the limitations, many researchers have focused on the development of new immunological and molecular based rapid assays that could enable early diagnosis of infection and accurate identification of fungal pathogens causing superficial and invasive infection. In this brief review, we highlighted the advantages and disadvantages of conventional diagnostic methods and possibility of non-culture based assays in diagnosis of superficial fungal infections and presented the overview on currently available immunochromatographic assays as well as availability of biomarkers detection by immunodiagnostic procedures in prompt and accurate diagnosis of invasive fungal infections. In addition, we presented diagnostic efficiency of currently available molecular panels and researches in this area.