Abnormal aminopyrine metabolism in patients with hepatic neoplasm. Detection by breath test.

Aminopyrine metabolism was assessed by the aminopyrine breath test (ABT) in 153 patients with malignant disease, of whom 75 had hepatic neoplasm and 78 had none. Radioactive carbon dioxide (14CO2) exhalation was measured two hours after oral administration of a trace dose of carbon-14 labeled aminopyrine. The ABT was correct in 62 of 75 (83%) patients with hepatic neoplasm and in 73 of 78 (94%) patients without. It was correct in 16 of 22 (73%) patients who had hepatic neoplasm without abnormal serum biochemistry. Aminopyrine metabolic clearance rate (AMCR) was 32.4 ml/min in patients with hepatic neoplasm and 103.4 +/- 18.8 ml/min in the patients without. There was a highly significant correlation between ABT and AMCR (r =.76, P less than .01). We conclude that aminopyrine metabolism is depressed in most patients with hepatic neoplasm and that the ABT affords a useful method for detecting malignant tumors of the liver.