Dual Analyte immunoassay--a new approach to neural tube defect and Down's syndrome screening.

A microtiter plate based Dual Analyte enzyme-immunoassay method for the simultaneous measurement of alpha-fetoprotein (AFP) and Free-beta human chorionic gonadotrophin (hCG) was evaluated. This rapid assay, which has application in both Neural Tube Defect screening and Down's screening, shows good precision with between assay coefficients of variation between 5 and 7.5% for AFP and 3.7 to 5.8% for Free-beta(hCG). Correlation with single analyte procedures is good, with correlation coefficients being greater than 0.91 in both cases. Clinical discrimination in detecting both types of abnormalities is not compromised by this new simultaneous Dual Analyte assay. We conclude that the Dual Analyte approach, which combines analytes achieving the highest known detection efficiency, will bring about improvements in the efficiency of screening, reduce costs and improve report turnaround, all leading to better quality of patient care.