Pretreatment of Serum Using a Microplate for Fractional Determination of Low Concentrations of α-Fetoprotein

An immunological pretreatment method using a microplate was developed for fractional determination of low concentrations of a-fetoprotein (AFP) in serum. This method allows simultaneous partial purification and concentration of AFP from many serum samples. The pretreated sample can then be subjected to lectin-affinity electrophoresis (LAE) coupled with detection by antibody-affinity blotting. More than 60% of the AFP was recovered by the partial purification from serum containing less than 100 pg/I of AFP, and the specific activities for the total protein was raised more than 20-fold. There was no bias or shift in AFP composition between the untreated and partially purified samples. By the present pretreatment method, AFP at a concentration of as low as 10 pg/I in serum was concentrated and detected by the LAE coupled with the antibody-affinity blotting.