[Assay of serum carbohydrate antigen (CA) 19-9 in the diagnosis of gastric cancer].

The levels of the serum carbohydrate antigen (CA) 19-9 were assayed in 284 cases including 77 patients with gastric cancer. The CA 19-9 levels were positive in 38% of gastric cancer cases, and they were significantly higher than those of benign gastric diseases. Extremely increased levels were found in advanced gastric cancer, but not in early gastric cancer. There was no significant correlation between CA 19-9 and CEA, and CA 19-9 seemed to be superior to CEA in specificity for gastric cancer, but inferior in sensitivity. Thus, the assay of CA 19-9 in combination with CEA could be helpful in the differentiation between benign and malignant gastric diseases.