Diagnosis of Ectopic Pregnancy by the Rate of Diagnostic Criteria Compared

We compare three methods for using the rate of change of human choriogonadotropin (hGG) concentration in serum to diagnose ectopic pregnancy. With Method I, the lower limit for the rate of increase of serum hCG in normal pregnancy is 66 % per 48 h. With Method Ii, a different lower limit of normal is specified for each of four discrete sampling interval of hCG. With Method iii, the lower limit of normal is determined by a continuous discnminant function of the initial hCG concentration. lithe initial hCG concentration is 2000 mt. units/L (Second International Standard), all three methods have acceptable diagnostic efficiencies, and there are no statistically significant differences among conclusions from the methods. None of the three methods performs satisfac-torily if the initial hCG concentration is>2000 mt.units/L. We recommend Method I because it is simpler than the othe