Evaluation of serum CA 19-9 in malignant tumors.

Abstract

Carbohydrate antigen (CA 19-9), a tumor-associated antigen by recently developed immunoradiometric assays utilizing monoclonal antibody 19-9, was evaluated in the serum of 42 healthy adults and 112 patients with and without malignant diseases. The assay is sensitive and simple to perform. The average coefficient of variation (CV) is 8.2% in a range of 5.8 to 120.0 units/ml. The minimum detectable dose is 4.8 units/ml and analytical recovery of CA 19-9 is 90%to 108%. The mean ±SD of the CA 19-9 in 42 healthy adults was 11.6±5.2 units/ml with a range of 5.6 to 28.4 units/ml. Based on a concentration of 37 units/ml as the upper normal limit, the false positive rate is 11.4%(4/35) and the true positive rates in malignancies were as follows: 100% (3/3) in pancreatic carcinoma. 100% (4/4) in cholangio-carcinoma, 50% (11/22) in colon carcinoma, 100% (3/3) in common bile duct carcinoma, 50% (4/8) in hepatocellular carcinoma, 40% (2/5) in liver metastasis, 7.7% (1/3) in gastric carcinoma, 0% (0/10) in lung carcinoma, 0% (0/2) in ovarian carcinoma, 0% (0/4) in adenocarcinoma of papilla of Vater and 0% (0/3) in esophageal carcinoma, respectively. The overall sensitively, specificity and diagnostic accuracy of CA 19-9 in the diagnosis of malignant tumors were 36.4%, 88.6%, and 52.7% respectively. It is concluded that CA 19-9 is a valuable tumor marker, especially in the diagnosis of pancreatic carcinoma, cholangio carcinoma and common bile duct carcinoma. However, non-malignant disease of the gall bladder (G.B) may also have elevated serum level of CA 19-9.