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

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.

• Publication year

  2019

• Venue

  American Journal of Gastroenterology

• Publication date

  2019-08-21

• Fields of study

  Medicine

• Identifiers
  DOI 10.14309/ajg.0000000000000384PMID 31449156PMCID 7192538
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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