Used in biomedical research to measure estriol (E3) levels in human biological samples such as serum, plasma, or urine. The kit enables quantitative detection of estriol, a key estrogen hormone, primarily for studies related to pregnancy, fetal development, and placental function. It is widely applied in clinical research settings to monitor hormonal changes during gestation, assess risk of preterm birth, and investigate endocrine disorders. The ELISA format allows for high sensitivity and specificity, making it suitable for large-scale screening and longitudinal studies. Not intended for diagnostic use.