Which condition is associated with an increase in ammonia levels in the blood?

An increase in ammonia levels in the blood is primarily associated with liver dysfunction. In normal physiology, ammonia, a byproduct of protein metabolism, is converted into urea in the liver, which is then excreted by the kidneys. Liver cirrhosis significantly impairs this conversion due to the liver's compromised function, leading to an accumulation of ammonia in the bloodstream.

While gastrointestinal hemorrhage can potentially lead to increased ammonia due to breakdown of blood proteins, it is the liver’s processing capability that predominantly determines ammonia levels. Conditions such as chronic kidney disease can also lead to altered ammonia levels, but primarily via different mechanisms related to protein metabolism and the body's inability to excrete nitrogenous waste, rather than direct synthesis issues as seen in liver disease.

In this context, the increased ammonia levels are most directly linked to liver cirrhosis, where the liver's reduced ability to detoxify ammonia is the critical factor.