An Optimised Radioimmunoassay for mAternal Serum α₁-Fetoprotein using Polyethylene Glycol

Abstract

SUMMARY A radioimmunoassay for cxl-fetoprotein in human maternal serum at 15-20 weeks' gestation using polyethylene glycol to separate bound and free antigen is described. A number of variables has been investigated to define optimal conditions for use at this gestation. The method gives results which agree with those from a double-antibody technique. It has good precision in the critical concentration range, and recoveries are satisfactory. The importance of including sufficient serum protein in the analytical system is stressed.There were systematic differences between three standard preparations of cxl-fetoprotein, but three out of four antisera tested gave very similar results. The implications for screening for neural tube defects in early pregnancy are discussed.

Denudations as paracellular routes for alphafetoprotein and creatinine across the human syncytiotrophoblast

“…Analysis of perfusate samples. The AFP concentrations in the perfusate samples were measured by the RIA technique used for clinical samples at St. Mary's Hospital (16). This RIA uses a well-characterized antibody that is unreactive with other serum proteins; the assay has a sensitivity of 2 ng/ml and a coefficient of variation of Ͻ10% at the analyte ranges used.…”