PIP: 2678 urines from pregnant and nonpregnant women were tested using a direct latex agglutination method of detecting the presence of human chorionic gonadotropin (HCG). In the direct latex agglutination reaction the anti-HCG serum is adsorbed on the polystyrene latex particles to produce direct agglutination of the latex particles in the presence of HCG in the test specimen. The test takes only a few minutes. In this series there was an accuracy of 97.7% in pregnant women and 99.5% in nonpregnant women. The overall accuracy rate was 98.5%. Semiquantitative studies of urinary HCG excretion were performed to anticipate prognosis of threatened abortion. Agglutination of a 1:8 urine dilution was tested in parallel with undiluted urine. Pregnancy was successfully continued at positive results at both dilutions in 89.5%. Abortion occurred in 85.7% when there was a positive reaction for undiluted urine but a negative reaction for the dilution. The time required to form the agglutination was also recorded for 885 pregnancies. In 83.6% the time required was 1 minute. The time required was between 1-3 minutes for 14.9% and greater than 3 monutes in 1.5%. All the pregnancies reacting in 1 minute progressed normally. Of those requiring 2 or 3 minutes, 8.3% had toxemia of pregnancy and 22.7% aborted spontaneously later.