Emergency serum and urine HCG analyses with the 'Tandem ICON' procedure.

A comparison between new urine and serum enzyme immunoassay techniques and existing serum radioimmunoassay techniques for the detection of HCG in the diagnosis of ectopic and early intrauterine pregnancy was undertaken. Urine HCG estimations by enzyme immunoassay were not found to be adequate for the exclusion of ectopic pregnancy due to a false negative rate of 12.5% (2 of 16 patients). Serum HCG estimations by enzyme immunoassay were found to compare favourably with radioimmunoassay techniques in the detection of HCG in both ectopic and early intrauterine pregnancy.