[Clinical evaluation of CA 19-9 for the detection of malignant tumors--a comparison with CEA and IAP].

To evaluate the ability of CA 19-9 to detect tumor antigen, sera from 122 patients with malignant tumors and 38 control patients were tested. The sensitivity of the test was compared with conventional CEA and IAP assays. The incidence of positivity in malignant tumors was 32.8% for CA 19-9 and 36.6% and 65.6% for CEA and IAP, respectively. The false-positive was 5%, 21% and 50% for CA 19-9, CEA and IAP, respectively. The highest positivity rate (75%) was observed in pancreatic cancers. Our results suggest that CA 19-9 is a useful marker for the detection of cancers.