That speed and simplicity contrast with the traditional diagnostic toolkit, which combines chest imaging, blood tests, respiratory samples collected during bronchoscopy and, sometimes, tissue biopsy. Some of these procedures are invasive, and even together they can leave clinicians uncertain.

The FDA cleared the test for use in adults with suspected IA, and it is intended to work alongside clinical findings, imaging and other laboratory tests — not to replace them.

How accurate was it?

The researchers validated the assay using frozen urine samples from 290 participants enrolled in studies in the United States and Belgium between 2009 and 2022. Laboratories in Baltimore, Pittsburgh and Raleigh, North Carolina, performed the testing.

The results:

• 50 participants had confirmed IA; the urine test correctly identified 46 of them (92%). Four cases came back falsely negative.
• Of the 240 participants without IA, the test correctly flagged 218 of 249 samples (88%) as negative. The slight discrepancy in sample counts reflects repeat testing.

A second phase examined how the assay performs in real clinical conditions. Between January 2023 and February 2024, the team analyzed 171 fresh urine samples from 168 eligible patients at The Johns Hopkins Hospital who were suspected of having IA, many with blood cancers or autoimmune diseases.

In that real-time setting, the test correctly identified six of seven (86%) confirmed positive cases and 35 of 39 (90%) confirmed negative cases. Notably, among the roughly half of suspected patients who never received a confirmed diagnosis, about 1 in 4 tested positive — a signal the researchers say demonstrates the tool's practical value in a hospital, where definitive evidence is often missing.

What are the limits?

The test misses a small share of infections, as the four false negatives in the validation study show, and it cannot rule IA in or out on its own. "This urine test is not a stand-alone answer, but it can provide another piece of evidence quickly and noninvasively," said Nitipong Permpalung, M.D., M.P.H., director of mycology research at the Johns Hopkins Transplant Research Center.

That evidence, he added, "could help us move faster for patients most likely to benefit from treatment while avoiding unnecessary antifungal exposure when infection is less likely."

The investigators are now studying how the assay performs in routine clinical care and whether it adds value for immunocompromised patients evaluated for fungal complications after respiratory viral infections. This work aligns with goals the World Health Organization set in 2022, when it added Aspergillus fumigatus to its list of critical-priority fungal pathogens to improve diagnosis, treatment and prevention worldwide.