From the Guidelines
Normal serum ammonia levels are typically considered to be ≤35 µmol/L. This is based on the most recent and highest quality study available, which provides a clear guideline for the management of hyperammonaemia in pediatric patients receiving continuous kidney replacement therapy 1. The study highlights that blood ammonia concentrations ≤35 µmol/l are considered normal, whereas high concentrations can produce toxic effects. Key points to consider include:
- Normal serum ammonia levels can vary slightly between different laboratories
- Elevated ammonia levels can indicate liver dysfunction or other conditions such as urea cycle defects
- Symptoms of hyperammonemia include confusion, lethargy, vomiting, and in severe cases, coma
- Blood samples for ammonia testing should be collected carefully and analyzed promptly to avoid false elevations Another study published in 2022 also supports the importance of measuring blood ammonia levels in patients with liver disease and acute encephalopathy, highlighting the negative predictive value of a normal blood ammonia level 1. However, the most recent and highest quality study 1 provides a clear and direct answer to the question, which is that normal serum ammonia levels are typically considered to be ≤35 µmol/L.
From the Research
Normal Serum Ammonia Levels
- The normal serum ammonia level is approximately 30 µM, or 30 μmol/L, as stated in the study 2.
- Another study mentions that mildly elevated ammonia levels can be around 39 μmol/L, with normal levels being less than 35 μmol/L 3.
- Elevated ammonia levels are generally considered to be above 72 μmol/L, according to the study 4.
- It is also noted that an elevated ammonia level in blood (100 micromol/L or higher) is an indicator of an abnormality in nitrogen homeostasis 5.