Results of the first 1000 radioreceptorassays for the determination of human chorionic gonadotropin: a new, rapid, reliable, and sensitive pregnancy test.

One thousand radioreceptorassays for human chorionic gonadotropin (hCG) for the diagnosis of pregnancy were analyzed under eight categories. The high sensitivity (50 pg/ml) and specificity, coupled with performance time of the assay (1 hour), provided a new modality for the early diagnosis and management of normal and abnormal pregnancy in the first trimester. The radioreceptorassay becomes positive 1 week after conception. In the normal pregnancy this assay has been 100% correct at the time of the first missed menses. All ectopic pregnancies demonstrated positive tests, and no false negatives occurred. On the other hand, a negative assay excluded ectopic pregnancy.