Comparison of the Analytical Characteristics of Ten Urinary hCG Tests for Early Pregnancy Diagnosis

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 immunoenzymetric (IEMA) ‘sandwich’ assays, or (haem/latex) agglutination (HA, LA)-inhibition (HAI, LAI) for the other systems provide assay sensitivities from 1000–50 IU/L within 3–120 min. The ‘best’ slide-(i.e., LA, LAI), haem-(i.e., HA, HAI) and IEMA-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 α- and β-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.