The influence of continuous renal replacement therapy on 1,3-β-d-glucan levels in critically ill patients: a single-center retrospective propensity score study

1,3-β-d-Glucan (BDG) is commonly used for diagnosing invasive fungal infections (IFIs). While exposure to cellulose-based hemodialyzers is known to cause false-positive BDG results, the impact of modern hemofilters used in continuous renal replacement therapy (CRRT) remains unclear. This retrospective, single-center cohort study aimed to evaluate the effect of CRRT on BDG levels in critically ill patients. We included adult intensive care unit (ICU) patients with ≥1 BDG measurement between December 2019 and December 2020. The primary outcome was the rate of false-positive BDG results in patients exposed to CRRT compared to unexposed patients. Propensity score analysis was performed to control for confounding factors. A total of 103 ICU patients with ≥1 BDG level were identified. Most (72.8%) were medical ICU patients. Forty patients underwent CRRT using hemofilter membranes composed of sodium methallyl sulfonate copolymer (AN 69 HF) (82.5%) and of polyarylethersulfone (PAES) (17.5%). Among the 91 patients without proven IFI, 31 (34.1%) had false-positive BDG results. Univariable analysis showed an association between CRRT exposure and false-positive BDG results. However, the association between CRRT exposure and false-positive BDG results was no longer significant across three propensity score models employed: 1:1 match (n = 32) (odds ratio (OR) 1.65, p = .48), model-adjusted (n = 91) (OR 1.75, p = .38), quintile-adjusted (n = 91) (OR 1.78, p = .36). In this single-center retrospective analysis, exposure to synthetic CRRT membranes did not independently increase the risk of false-positive BDG results. Larger prospective studies are needed to further evaluate the association between CRRT exposure and false-positive BDG results in critically ill patients with suspected IFI.

Serum (1,3)-Beta-d-Glucan has suboptimal performance for the diagnosis of Pneumocystis jirovecii pneumonia in cancer patients and correlates poorly with respiratory burden as measured by quantitative PCR

OBJECTIVE

Non-HIV immunocompromised patients with Pneumocystis jirovecii pneumonia (PCP) have lower fungal load than those with AIDS, potentially affecting the accuracy of diagnostic biomarkers. Therefore, we investigated the performance of serum (1,3)-Beta-d-Glucan (BDG) in conjunction with quantitative Pneumocystis jirovecii PCR (qPCR) in non-HIV cancer patients.

METHODS

We reviewed records of non-HIV cancer patients and classified them as definite, probable, or possible PCP cases, according to clinicoradiological features, microscopy findings, and qPCR results in bronchoscopy specimens. We evaluated the diagnostic performance of serum BDG and its correlation with qPCR results.

RESULTS

We identified 101 PCP patients (73 definite/probable, 28 possible) and 74 controls. Correlation of BDG and qPCR was low among all 101 qPCR-positive patients (Spearman's = 0.38) and in definite/probable PCP cases (Spearman's = 0.18). Considering all qPCR-positive patients, BDG showed consistently low sensitivity at different cutoffs. Among definite/probable cases, the diagnostic accuracy of BDG remained poor, yet slightly improved with high qPCR thresholds (AUC = 0.86 at ≥2000 DNA copies/mL). BDG had a low PPV but excellent NPV across different qPCR and BDG cutoffs.

CONCLUSIONS

BDG and qPCR levels correlate poorly in non-HIV cancer patients with PCP. BDG diagnostic performance is suboptimal but a negative test may be useful to rule out PCP in this population.

Blood product transfusions are associated with an increase in serum (1-3)-beta-d-glucan in infants during the initial hospitalization in neonatal intensive care unit (NICU)

INTRODUCTION

Serum (1-3)-beta-d-glucan (BDG) assay has been proposed as an adjunct for the rapid diagnosis of invasive fungal infection (IFI). However, false-positive results have been reported following transfusion of blood products in adults.

AIMS

To assess the relationship between blood product transfusion and elevated BDG in neonates.

METHOD

Retrospective study including neonates ≤32 weeks, with no fungal colonization or infection, in whom BDG assay was performed for suspicion of IFI. Patients were classified in Transfusion (n = 78) and No Transfusion (n = 55) groups depending on whether or not they were transfused. Clinical, biochemical and microbiological characteristics were recorded. A BDG assay >80 pg/mL was considered as positive.

STATISTICAL ANALYSES

bivariate and multivariate logistic regression. Results (median, IQR): One hundred and thirty-three infants were included (gestational age 28.4 weeks, 26.9-30; birth weight 1000 g, 847-1300). BDG was higher in the Transfusion group (170 pg/mL, 65-317) than in the No Transfusion group (57 pg/mL, 34-108; p < 0.001). False-positive BDG assay results were associated with red blood cells (RBC) and fresh frozen plasma (FFP) transfusions.

CONCLUSION

BDG is increased after RBC and FFP transfusions in neonates, leading to overdiagnosis of IFI. Fungal colonization status in peripheral sites and central cultures could help to reduce the risk of misdiagnosis.