# Diagnostic Challenge for Positive 1,3-β-D-Glucan in an Immunocompromised Patient Receiving Intravenous Immunoglobulin Presenting With Respiratory Failure

## TL;DR

A patient with a weak immune system had a confusing positive test for a fungal infection due to IVIG treatment, highlighting the need for careful interpretation of test results.

## Contribution

This case highlights the diagnostic challenge of BDG testing in immunocompromised patients receiving IVIG.

## Key findings

- The patient's BDG test was positive, but IVIG use complicated the interpretation.
- Empirical treatment for PJP was initiated due to the inability to perform bronchoscopy.
- The case emphasizes the need for caution when interpreting BDG results in similar clinical scenarios.

## Abstract

Diagnosing Pneumocystis jirovecii pneumonia (PJP) can be complex, particularly in cases of significant respiratory failure. The 1,3-β-D-glucan (BDG) serum assay has emerged as a promising non-invasive diagnostic tool for detecting fungal infections, including PJP. However, factors that can confound the interpretation of BDG levels by causing elevation in serum levels have been documented. Here, we present the case of 51-year-old woman with underlying autoimmune disorder, hematologic malignancy, and chronic steroid use, who was admitted for acute hypoxemic respiratory failure. Obtaining the BDG assay after the administration of intravenous immunoglobulin (IVIG) posed a diagnostic challenge, as the patient was unable to undergo bronchoscopy. This circumstance led to a debate regarding the possibility of a false-positive BDG due to IVIG use or the presence of PJP. Ultimately, the patient was empirically treated for PJP. This case underscores the importance of comprehending factors that may contaminate BDG results, particularly in immunocompromised individuals.