A new latex-inhibition slide test for pregnancy, Gest female State, with the use of polystyrene latex particles to which human chorionic gonadotropin (hCG) has been bound, is described. The sensitivity of this test was found to be 2 to 4 1.U. of hCG per milliliter of urine. Clinical trials with the Gest female State in urine samples from 328 patients (203 positive, 125 negative) showed one false negative and no false positive results. Urine containing drugs or high concentrations of various ingredients and abnormal urine did not result in interference with expected test results. The new test was comparable with or superior to other commercially available rapid slide tests for pregnancy.