Comparison of the analytical characteristics of ten urinary hCG tests for early pregnancy diagnosis

SUMMARY. A comparison of assay design, sensitivity and specificity is given for 10 urinary human chorionic gonadotrophin (hCG) test kits for early pregnancy diagnosis. One slide test applies a polyclonal anti-hCG serum, while nine, more recently developed, tube and slide tests use one or more monoclonal antibodies toward intact hCG or its free subunits. Colour development for five immunoen­ zymetric (lEMA) 'sandwich' assays, or (haem/latex) agglutination (HA, LA)­ inhibition (HAl, LAJ) for the other systems provide assay sensitivities from lOaD-50 lU/L within 3-120 min. The 'best' slide-(i.e., LA, LAI), haem-(i.e., HA, HAl) and lEMA-tests detect respectively 500, 75 and 50 IU/L within 2,5, 120 and 3 min. Assay specificities (i.e., as false-positive and false-negative test results) are studied using intact hCG, hLH and their free a- and ~-subunits. The presented assays are improved, perform more sensitively at shorter reaction times with increased specificity, and may, therefore, establish pregnancy at an earlier stage . with greater reliability.