2025/10/01 by Ciselle Meier, Catherine Manolikos, Kharis Burns +1 · 1 voice
Biochemistry, Genetics and Molecular Biology · Medicine · #Folate and B Vitamins Research #Liver Disease and Transplantation #Metabolism and Genetic Disorders
paper · doi:10.1111/1742-6723.70153
openalex publication_date 2025/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
OBJECTIVE: Serum ammonia concentration is useful to identify adult onset inherited metabolic disorders in patients with encephalopathy, which are currently under-recognised. We investigated the current ammonia requesting practises in an Australian Tertiary Hospital Emergency Department (ED) to determine if hyperammonemia is being considered in adults presenting with non-hepatic encephalopathy. METHODS: A retrospective chart review was performed on all adult patients with a serum ammonia requested from a single tertiary ED over a 12 month period. The indications for ammonia testing, site of collection (ward vs. emergency department) and aetiology of hyperammonemia were recorded. An elevated serum ammonia level was defined as > 60μmol/L. RESULTS: A total of 597 serum ammonia tests were drawn from 439 patients, of which 177 (29.6%) tests were from patients with known inherited metabolic disorders. Ammonia ordering was higher on the ward (77.5%) than in the ED (22.5%); however, the ED had a higher proportion of orders with a hepatic indication for testing (89.8% vs. 63.4%). There were 666 emergency department presentations for confusion/coma or encephalopathy. Of these patients, 52 (7.8%) had an ammonia measured, 25 (3.8%) from ED. Other indications for ammonia measurement included valproate toxicity, altered mental status, seizures, and atypical neurological symptoms. No new cases of suspected metabolic disease were identified. CONCLUSION: Ammonia testing from the ED remains predominantly in the assessment of patients with hepatic disease, which is not a guideline-recommended indication. Serum ammonia concentration is underutilised in cases of encephalopathy of unclear aetiology, potentially leading to missed diagnoses of metabolic disease.