A device for measuring human breath ammonia was developed based on a single use, 
disposable, inkjet printed ammonia sensor fabricated using polyaniline 
nanoparticles. The device was optimized for sampling ammonia in human breath 
samples by addressing issues such as variations in breath sample volume, flow 
rate, sources of oral ammonia, temperature and humidity. The resulting system 
was capable of measuring ammonia in breath from 40 to 2993 ppbv (r(2 )= 0.99, n 
= 3) as correlated with photoacoustic laser spectroscopy and correlation in 
normal human breath samples yielded a slope of 0.93 and a Pearson correlation 
coefficient of 0.9705 (p < 0.05, n = 11). Measurement of ammonia in the breath 
of patients with end-stage kidney disease demonstrated its significant reduction 
following dialysis, while also correlating well with blood urea nitrogen (BUN) 
(r = 0.61, p < 0.01, n = 96). Excellent intraindividual correlations were 
demonstrated between breath ammonia and BUN (0.86 to 0.96), which demonstrates 
the possibility of using low cost point of care breath ammonia systems as a 
noninvasive means of monitoring kidney dysfunction and treatment.