Objective: To develop and validate an assay for urinary luteinizing hormone (LH) metabolite that can be used for frozen-thawed urine.
Design: The study is in two parts: (1) selected urine samples were evaluated to determine all components of urinary LH metabolism, and then (2) 26 complete menstrual cycles were evaluated using daily matched blood and urine samples.
Setting: Urinary and serum samples were collected for normal women undergoing artificial insemination because of the infertility of their partners.
Patients: Patients were selected to have normal ovarian function.
Intervention: None.
Main outcome: Serum LH and urinary LH metabolites were measured in daily samples from 25 ovulatory cycles.
Results: The midcycle serum LH peak was highly correlated to the measurement of urinary LH metabolites in frozen:thawed urine samples.
Conclusion: A simple enzyme assay for LH/LH-alpha can be used to detect the midcycle LH surge on frozen-thawed urine samples. This method has practical application in a situation that involves self-collected urine samples stored frozen and later analyzed to determine the day of ovulation.