Detection of urinary human chorionic gonadotropin by rapid immunoconcentration method is the first-line test for suspected ectopic pregnancy.

Nine hundred nine patients with suspected ectopic pregnancy were tested for human chorionic gonadotropin (hCG) using two qualitative assays: the Tandem Icon urine assay (Hybritech, San Diego, CA) and a serum radioimmunoassay (RIA) employing a positive cut-off of 25 IU/l. Pregnancy status was determined by clinical or histologic examination, or detection of hCG or its metabolites in four quantitative immunoassays: two RIAs and two immunoradiometric assays (IRMAs). Both the Tandem Icon and the qualitative RIA detected all 71 patients with ectopic pregnancy. The predictive indices of the Icon were 100% for a positive result and 99.6% for a negative result, and those of the RIA were 96.7 and 99.6%, respectively. The Tandem Icon thus fulfils the need for a simple, rapid, and sensitive method for hCG in the detection of patients with suspected ectopic pregnancy.