Receiver-operator characteristic, efficiency analysis, and predictive value of serum progesterone concentration as a test for abnormal gestations.

Objective: Our objective was to determine if a discriminatory progesterone concentration could be established that confidently predicted abnormal early gestations.

Study Design: We analyzed differences in progesterone concentrations between normal (n = 40) and abnormal (n = 34) pregnancies during the first 49 days of gestation. The receiver-operator characteristic curve, test efficiency, and predictive value of serum progesterone to discriminate between an abnormal and normal first-trimester gestation were calculated for progesterone concentrations between 5 and 25 ng/ml.

Results: Receiver-operator characteristic curve analysis indicated that the best discriminatory progesterone concentration was 10 ng/ml. Test efficiency was maximum between serum progesterone concentration of 9 to 14 ng/ml (80%). When progesterone was less than 10 ng/ml, the predictive value of the abnormal test result was greater than 90%.

Conclusion: Receiver-operator characteristic analysis, test efficiency, and the predictive value of an abnormal test result suggest that the best progesterone cut off point that predicts abnormal early pregnancies is 10 ng/ml.