Variability and Lability of Ammonia Levels in Healthy Volunteers and Patients With Cirrhosis: Implications for Trial Design and Clinical Practice. (21st August 2019)

• Record Type: Journal Article
• Authors: Bajaj, Jasmohan S.; Bloom, Patricia Pringle; Chung, Raymond T.; Hassanein, Tarek I.; Padilla-Martinez, Marielys; Kayali, Zeid; Rockey, Don C.; Sasso, Roula; Muthukumar, Alagar R.; Lee, William M.; Denney, William S.; Gavis, Edith A.; Anderson, Cami; Blankstein, Larry; Brennan, Aoife M.; Puurunen, Marja K.; Lawitz, Eric
• Is Part Of: American journal of gastroenterology. Volume 115:Number 5(2020)
• Page Start: 783
• Page End: 785
• Publication Date: 2019-08-21
• Subjects: Stomach -- Diseases -- Periodicals; Intestines -- Diseases -- Periodicals; Gastroenterology -- Periodicals; Gastrointestinal Diseases -- Periodicals; Electronic journals; Periodicals; 616.33
• DOI: 10.14309/ajg.0000000000000384
• Languages: English
• ISSNs: 0002-9270

Abstract

Abstract : Introduction: Ammonia levels are used to assess hepatic encephalopathy, but their levels are highly variable in clinical practice. Methods: We studied factors associated with variation in ammonia values in cirrhotic patients without previous hepatic encephalopathy and healthy volunteers (HVs). Results: Ammonia increased by 12% and 18% at 1 and 2 hour, respectively, after a protein meal in 64 cirrhotic patients ( P < 0.001). In 237 HVs, ammonia levels varied significantly between sites ( P < 0.0001). New site-specific ammonia upper limits based on HV levels using a strict analysis protocol differed from routinely used values. Correlation between paired fresh samples was high (r = 0.83) but modest between fresh and frozen samples (r = 0.62). Discussion: Sample handling, processing, and protein intake impact ammonia levels across sites.