title: Breath-ammonia testing of healthy subjects and patients with cirrhosis.
abstract: BACKGROUND
  Hepatic encephalopathy (HE) is a serious neuropsychiatric complication in both acute and chronic liver disease.
  
  
  OBJECTIVE
  To establish the utility of a portable noninvasive method to measure ammonia in the breath of healthy subjects and patients with HE.
  
  
  METHODS
  The study included 106 subjects: 44 women and 62 men, 51 healthy and 55 cirrhotic. The breath ammonia was measured with an electrochemical sensor and expressed in parts/billion (ppb).
  
  
  RESULTS
  The breath ammonia in healthy subjects had an average value of 151.4 ppb (95% confidence interval [CI]: 149.4-153.4) and the average value in cirrhotic patients was 169.9 ppb (95% CI: 163.5-176.2) (P < 0.0001). In cirrhotic patients with and without HE, the corresponding values were 184.1 ppb (95% CI: 167.7-200.6) and 162.9 ppb (95% CI: 158.8-167.0), respectively (P = 0.0011). Ammonia levels ≥ 165 ppb permitted a differentiation between healthy and cirrhotic subjects; the area under the receiver operating characteristic (ROC) curve for the ammonia-level values in cirrhotic versus control patients was 0.86 (95% CI: 0.79-0.93). In cirrhotic patients, ammonia levels ≥ 175 ppb permitted the distinction between patients with and without HE; the area under the ROC curve in cirrhotic patients with versus without HE was 0.83 (95% CI: 0.73-0.94).
  
  
  CONCLUSIONS
  A portable sensor for measuring breath ammonia can be developed. If the results of the present study are confirmed, breath-ammonia determinations could produce a significant impact on the care of patients with cirrhosis and could even include the possibility of self-monitoring.
authors.affiliation: Hepatology Centre, Calle 37 Nro 926, B1902AWL, La Plata, Argentina. raul.adrover@gmail.com
authors.forename: R
authors.initials: R
authors.lastname: Adrover
authors.forename: D
authors.initials: D
authors.lastname: Cocozzella
authors.forename: E
authors.initials: E
authors.lastname: Ridruejo
authors.forename: A
authors.initials: A
authors.lastname: García
authors.forename: J
authors.initials: J
authors.lastname: Rome
authors.forename: J J
authors.initials: JJ
authors.lastname: Podestá
mesh_terms: D000328:Adult; D000368:Aged; D000641:Ammonia / Q000378:metabolism*; D001944:Breath Tests / Q000295:instrumentation / Q000379:methods*; D016022:Case-Control Studies; D015897:Comorbidity; D003362:Cost-Benefit Analysis; D005260:Female; D006501:Hepatic Encephalopathy / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000453:epidemiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve
chemical_list: D000641:Ammonia