The document discusses a method called alkaline hematin for quantitatively measuring menstrual blood loss, which is commonly used as an endpoint in clinical trials for conditions like menorrhagia, endometriosis, and uterine fibroids. The method involves measuring the absorbance of hematin extracted from used feminine hygiene products. KCAS has validated this alkaline hematin assay according to FDA standards and has experience measuring over 137,000 samples from more than 10,000 menstrual cycles using this method. Their validated method and data have supported FDA approval for several drugs and devices.