Variability and Lability of Ammonia Levels in Healthy Volunteers and Patients With Cirrhosis: Implications for Trial Design and Clinical Practice

Jasmohan S. Bajaj, Patricia Pringle Bloom, Raymond T. Chung, Tarek I. Hassanein, Marielys Padilla-Martinez, Zeid Kayali, Don C. Rockey, Roula Sasso, Alagar R. Muthukumar, William M. Lee, William S. Denney, Edith A. Gavis, Cami Anderson, Larry Blankstein, Aoife M. Brennan, Marja K. Puurunen, Eric Lawitz

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Pages (from-to)783-785
Number of pages3
JournalThe American Journal of Gastroenterology
Volume115
Issue number5
DOIs
StatePublished - May 1 2020

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

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    Bajaj, J. S., Bloom, P. P., Chung, R. T., Hassanein, T. I., Padilla-Martinez, M., Kayali, Z., Rockey, D. C., Sasso, R., Muthukumar, A. R., Lee, W. M., Denney, W. S., Gavis, E. A., Anderson, C., Blankstein, L., Brennan, A. M., Puurunen, M. K., & Lawitz, E. (2020). Variability and Lability of Ammonia Levels in Healthy Volunteers and Patients With Cirrhosis: Implications for Trial Design and Clinical Practice. The American Journal of Gastroenterology, 115(5), 783-785. https://doi.org/10.14309/ajg.0000000000000384