Standard serum concentrations and normal fluctuations of CEA, CA 50 and CA242 during twelve months in men and women aged 60-64 years without malignant disease

Objective: To establish standard serum concentrations of carcinoembryonic a ntigen (CEA), carbohydrate antigen (CA) 50 and CA 242 in cancer-free subjec ts in the age group during which cancers are likely to develop. Design: Prospective study. Setting: University hospital, Sweden. Interventions: Blood samples obtained by venepuncture on four occasions dur ing one year. Main outcome measures: Consultation with the Regional Cancer Registry to ex clude those who had previously had malignant disease diagnosed or developed cancer during and up to two years after the end of the clinical part of th e study. Serum concentrations of CEA, CA 50, and CA 242. Results: The 90th centile was 5.6 ng/ml for CEA, 30.1 U/ml for CA 50, and 2 4.5 U/ml for CA 242. The mean (SD) serum concentrations were 2.6 ng/ml (2.2 ) for CEA, 13.2 U/ml (11.4) for CA 50, and 10.6 U/ml (9.6) for CA 242. Seru m concentrations of CEA were significantly higher (p < 0.001) among smokers . The intraindividual fluctuations were 16%, 16%, and 14%, respectively. Conclusions: Serum concentrations of CEA, CA 50, and CA 242 were higher in this study than previously reported, probably because the subjects were old er than in other reports. The fluctuations were small. Serum concentrations of CEA were higher in smokers than in non-smokers.