Background/objective While ammonia plays a role in the complex pathophysiology of hepatic encephalopathy (HE), serum ammonia is unreliable for both diagnosis of, and correlation with, neurological symptoms in patients with cirrhosis. We aimed to quantify ordering, cost and appropriate use of serum ammonia in a major Midwestern healthcare system.
Design/method Serum ammonia ordering in adult patients presenting to a large Midwestern health system was evaluated from 1 January 2015 to 31 December 2019.
Results Serum ammonia ordering was prevalent, with 20 338 tests ordered over 5 years. There were no differences in the number of inappropriate serum ammonia tests per 100 000 admissions for chronic liver disease over time (Pearson’s correlation coefficient=−0.24, p=0.70). As a proportion of total ammonia tests ordered, inappropriate tests increased over time (Pearson’s correlation coefficient=0.91, p=0.03). Inappropriate ordering was more common at community hospitals compared with the academic medical centre (99.3% vs 87.6%, p<0.001).
Conclusion Despite evidence that serum ammonia levels are unreliable for the diagnosis of HE and are not associated with severity of HE in individuals with cirrhosis, ordering remains prevalent, contributing to waste and potential harm.
- hepatic encephalopathy
Data availability statement
Data are available on reasonable request. Not applicable.
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Contributors Role in the Study: Study concept and design (EA and NL); acquisition of data (EA and NL); analysis and interpretation of data (EA and NL); drafting of the manuscript (EA, NL); critical revision of the manuscript for important intellectual content (EA, NL and APJO); statistical analysis (EA and NL); obtained funding (not applicable).
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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