Performance of a new enzyme-linked immunoassay urine pregnancy test for the detection of ectopic gestation

An enzyme-linked immunoassay urine pregnancy test was used on a group of patients suspected of having an ectopic pregnancy. Patients were seen in the county hospital emergency department and had the urine test correlated with a serum beta-hCG level determined by radioimmunoassay. There were 884 patients with urine ICON-serum beta-hCG correlations. The ICON was positive in each of the 247 patients whose serum value was over 50 mIU/mL, and was negative in each of the 619 patients whose serum level was below 5 mIU/mL. Eighteen patients had a serum level between 10 and 50 mIU/mL and the ICON was positive in 13. The five patients with a low serum beta-hCG level and a negative ICON had dilute urine when tested. Using a modified testing procedure, each of these produced a positive ICON. Of the 27 patients with an ectopic pregnancy the urine ICON was positive in 26. The urine ICON is an improved assay for hCG in patients suspected of having an ectopic pregnancy, and is ideally suited for ED use.