Measurement of breath ammonia for detection of patients with chronic kidney disease

Abstract

Background: In a healthy individual, ammonia is converted to urea in the liver. Urea is then transported through the bloodstream and then excreted into the urine by the kidneys. In patients with chronic kidney disease (CKD), the accumulated urea is degraded by salivary urease into ammonia, which is then excreted by breathing. Breath ammonia can therefore be used for detecting the increased nitrogen-bearing wastes. In our pilot study, an electrochemical sensor was used to measure and analyze breath ammonia in healthy volunteers and patients with CKD.

Patients and methods: In our study, 8 patients with CKD (stages 4 and 5) and 6 healthy volunteers were enrolled. All participants were nonsmokers and without pulmonary or liver disease. One controlled breath sample was collected from each participant. Immediately after the sample was collected, a gas analyzer was used for measuring breath ammonia in our participants.

Results: Mean creatinine value of CKD patients was 455.2 ± 294.1 µmol/L and 62.1 ± 7.5 µmol/L for healthy volunteers. Breath ammonia levels (3.32 ± 2.19 ppm vs. 0.49 ± 0.08 ppm; p = 0.003) and measured electric current (4.33 ± 0.25 mA vs. 4.01 ± 0.01 mA; p = 0.003) were significantly higher in the CKD group.

Conclusions: The results of our pilot study show that breath monitoring of ammonia can be a simple, useful, fast, and noninvasive tool for detection of advanced kidney impairment. .