Venous blood ammonium levels in control subjects and in patients with disorders of the liver.

Venous blood ammonium levels were studied in 106 control subjects and 47 patients with varying degrees of liver disorder. The resting venous blood ammonium was normally distributed in both male and female control subjects and was not influenced by either the sex or the fasting state of the subject. In general it was also uninfluenced by age except that the level was found to be a little lower in subjects over 60 years of age probably due to their state of greater muscular inactivity. The mean resting ammonium level in controls was 80.0 mug/100 ml +/- 17.17 mug/100 ml and the range (mean +/- 2 SD) 46-114 mug/100 ml. Raised levels were obtained in 16.7% of patients with subclinical liver disorder, 62.5% with moderate liver disorder, and 85.5% with severe liver disorder, indicating a relationship between the severity of liver disorder and the resting venous blood ammonium level. As the majority of patients with severe liver disorder were known to have varices the raised ammonium levels are likely to have been related to the greater magnitude and incidence of portal systemic shunts in those with severe liver disease.