High blood-ammonia levels alone do not add any diagnostic, staging, or prognostic value in HE patients known to have chronic liver disease.
Sources:
Lockwood AH. Blood ammonia levels and hepatic encephalopathy. Metab Brain Dis. 2004 Dec;19(3-4):345-9. PMID: 15554426.
Vilstrup H, et al. Hepatic encephalopathy in chronic liver disease: 2014 Practice Guideline by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver. Hepatology. 2014 Aug;60(2):715-35. PMID: 25042402.