In a recent Perspective published in AJKD, Jaime Uribarri and colleagues review the literature on urinary ammonium excretion (UNH₄) in an attempt to establish reference values to interpret UNH₄ results if and when UNH₄ measurements become available as a routine clinical test. They also provide further evidence that the urinary anion gap is not a good predictor of UNH₄.

AJKDBlog’s Interviews Editor, Timothy Yau @Maximal_Change sat down with Drs. Jaime Uribarri @lowage and David S. Goldfarb @weddellite to discuss this topic.

If the embedded player above doesn’t work, please click here to watch the video interview.

Urinary rate of ammonium excretion versus urinary anion gap in (A) non–stone formers (n = 1,007; r² = 0.0005) and in (B) stone formers (n = 23,997; r² = 0.0056). Figure 1 from Uribarri et al, AJKD © National Kidney Foundation.

Special thanks to Drs. Uribarri and Goldfarb for taking the time to talk with us!

Title: Beyond the Urine Anion Gap: In Support of the Direct Measurement of Urinary Ammonium
Author: Jaime Uribarri, David S. Goldfarb, Kalani L. Raphael, Joshua L. Rein, and John R. Asplin
DOI: 10.1053/j.ajkd.2022.05.009