Caffeine elimination: a test of liver function.

Fasting plasma caffeine concentration and various parameters of caffeine elimination from plasma obtained after a standardized oral dose of 140 mg caffeine have been compared in nine patients with liver cirrhosis, eight patients with non-cirrhotic liver disease and ten healthy volunteers with regard to their ability to discriminate between the different groups. Fasting plasma caffeine concentrations were significantly higher in cirrhotics (11.1 +/- 10.5 mumol/l) than in healthy volunteers (1.5 +/- 0.8 mumol/l). The respective values measured in patients with non-cirrhotic liver disease (3.1 +/- 3.1 mumol/l) did not differ significantly from the controls. Plasma disappearance rate and clearance of caffeine were significantly decreased in cirrhotics (0.11 +/- 0.02 h-1; 1.0 +/- 0.3 ml/min per kg) and in patients with non-cirrhotic liver disease (0.18 +/- 0.04 h-1; 2.2 +/- 0.7 ml/min per kg) as compared to healthy volunteers (0.23 +/- 0.04 h-1; 3.1 +/- 0.9 ml/min per kg). Plasma caffeine concentration determined 12 h after administration of the test dosage discriminated best between patients with cirrhosis (5.4 +/- 1.6 mumol/l), patients with non-cirrhotic liver disease (2.0 +/- 1.4 mumol/l) and healthy volunteers (0.8 +/- 0.2 mumol/l). These results, the safety of the test compound and the simplicity of a single caffeine determination in plasma 12 h after a standardized dose of caffeine make this test attractive for evaluation of liver function.