Comparative Studies of Solid Phase Method and Double Antibody Method in CEA Radioimmunoassay

The comparative study between solid phase method and double antibody method in CEA radioimmunoassay was carried out. The results obtained were as follows. 1. The serum amount needed for the assay was larger in solid phase method than in double antibody method. 2. Before the assay procedure, a preparation of various reagents was required in double antibody method, but it was not necessary in solid phase method. 3. An extraction procedure of CEA was required in solid phase method, but it was not necessary in double antibody method. 4. Incubation temperature must be kept at 20℃ in double antibody method, but it was enough at room temperature in solid phase method. 5. The assay was completed within one or two days in solid phase method, but it was two or three days in double antibody method. 6. To express the binding ability in standard curve, B/T was adequate in solid phase method, but B/Bo was suitable in double antibody method. 7. The standard curve was almost correctly fitted from 1 to 100 ng/ml in solid phase method, but it was from 5 to 160 ng/ml in double antibody method. 8. In regard to accuracy, parallelism and recovery tests, good results were obtained in both methods. From the results obtained, both solid phase and double antibody methods were equally useful for CEA assay.