Wide variation in maternal serum alpha-fetoprotein reports in one metropolitan area: Concerns for the quality of prenatal testing

The variation in reported laboratory values, medians, and confounding variables used in the interpretation of alphafetoprotein (AFP) values from 14 laboratories servicing the Detroit-Metropolitan area was assessed by reviewing the laboratory report forms. The wide variation found in reported values, medians, and use of correction factors makes interpretation of results difficult and inaccurate. The need for large data bases for continuous correction of medians, uniform use of correction factors, and clinical decision making is emphasized.