Urinary Ammonium: A Renewed Compass for Renal and Extra-Renal Disorders, a Case Series

Lara Mary Titherington; Stefano Romagnoli; Pietro Caironi

doi:10.66224/rjccn.2.03.39

Authors

Lara Mary Titherington Department of Anesthesia and Intensive Care, Azienda Ospedaliero-Universitaria Careggi; Department of Health Science, University of Florence; Florence, Italy Author https://orcid.org/0009-0009-5470-6352
Stefano Romagnoli Department of Oncology, University of Turin, Turin, Italy Author
Pietro Caironi Department of Oncology, University of Turin, Turin, Italy Author

DOI:

https://doi.org/10.66224/rjccn.2.03.39

Keywords:

urinary electrolytes, ammonium, KING, renal transplant, chronic renal failure

Abstract

Introduction. Assessment of urinary ammonium (uNH4+) describes one of the kidney’s most important physiological functions, yet direct measurement is not routinely available. Historically, urine anion gap has been used as a surrogate for uNH4+, although this approach is unreliable, particularly in patients with chronic kidney disease. The ability to directly measure uNH4+ may therefore provide clinically relevant diagnostic and therapeutic information.
Case Series. In this case series, we present three clinical cases illustrating the utility of uNH4+ measurement, now available as
a bedside point-of-care measurement (KING, Kures®). These include comparison between a dysfunctional native kidney and
a recovering transplanted graft, and the differential diagnosis of a-lactic metabolic acidosis in two distinct clinical settings. Across
cases, uNH4+ provided timely physiological insight into tubular function, supporting diagnosis and recovery assessment beyond
traditional markers.
Conclusions. These observations underscore the importance of distinguishing tubular from glomerular function and complement
traditional markers in renal assessment.