Retention of carcinoembryonic antigen on Sephadex G-50 and acrylamide gel buffer-exchange columns

We compared the degree of retention of carcinoembryonic antigen on two types of buffer-exchange columns, Sephadex G-50 and acrylamide gel. Both types retained trace amounts of the antigen applied in the form of a perchloric acid extract, as measured by its release into plasma samples subsequently processed through the same columns, Cross contamination, resulting in values falsely high by greater than 1 microgram/L, was observed when columns were re-used after processing plasma samples with carcinoembryonic antigen concentrations greater than 700 micrograms/L.