A clinical approach to the use of predictive values in the prenatal diagnosis of neural tube defects

The rationale of calculating predictive values to interpret the amniotic fluid alpha-fetoprotein (AFP) test has been examined and applied to amniotic fluid AFP testing from one Canadian center. Such predictive value ccalculations may be misleading if they fail to make use of the actual magnitude of the test result or the results of other investigations. The alculation of predictive values has thus been extended to take into account magnitude of …