Abstract
An unselected series of 136 patients suspected of having a major intra-abdominal pathological condition had blood drawn and stored as serum. A definitive histo-logical diagnosis was made in all cases, usually by laparotomy. The serum was analysed with coded samples for carcino-embryonic antigen, alpha-fetoprotein and pancreatic oncofetal antigen and all recorded levels above the upper limit of normal for that test were taken as a positive result. Results were analysed to give the predictive value of a positive test and a negative test for each antigen. A negative pancreatic oncofetal antigen test was found to be useful in excluding a diagnosis of pancreatic cancer.