Evaluation of new serum and urine tests in cases of suspected pathologic early pregnancy

Two pregnancy tests, ModEL serum hCG Assay and ModEL Urine hCG Assay, were evaluated using sera and urine from 46 patients suspected of pathologic early pregnancy, of whom 22 patients had spontaneous abortion and 9 an ectopic pregnancy. ModEL Serum hCG Assay had a 100% sensitivity and specificity, thus demonstrating its value in these cases. With a sensitivity of 94% and a specificity of 87%, ModEL Urine hCG Assay gave poorer results. Both tests have a relative high "detection limit" of 25 U/l (serum) and 50 U/l (urine) which may impair their ability to distinguish between presence and absence of pregnancy by very low levels of hCG.