Diagnostic accuracy of a new tumor serologic marker, CA 19-9: comparison with CEA.

Two hundred and twenty-one hospitalized patients underwent serum determination of CA 19-9, a recently developed tumor marker assay, and CEA. Among these, 53 had a gastrointestinal (GI) cancer, 59 a GI benign disease, 52 a non-GI cancer, and 57 a non-GI benign disease. CA 19-9 assay was more accurate than CEA to detect malignancy, especially of GI source (69.8% sensitivity vs. 24.5% in GI patients); when a cutoff level of 41 ng/ml for CA 19-9 was considered, only 6 false-positive cases were found and both markers showed excellent specificity (94.9% for CEA and 89.9% for CA 19-9 in gastric, hepatobiliary and pancreatic cancer). We conclude that CA 19-9 is a useful GI tumor marker and it seems to be better than CEA in some pathologic situations.