Effects of Storage Conditions on Urinary LH and FSH Measurement Using Immunochemiluminometric Assay.

BACKGROUND: Urine is a good alternative body fluid for gonadotropin studies. There was limited information about the effects of different storage conditions on urinary gonadotropin measurement by using immunochemiluminometric assay (ICMA). METHODS: ICMA was used to determine gonadotropin in urine stored under different conditions, such as different pH, storage time, and cycles of freeze-thaw. RESULTS: Luteinizing hormone (LH) level was not significantly affected at pH 2.5 to 10.5 or being stored at 4°C for 3 days. Follicular stimulating hormone (FSH) level was not significantly changed at pH 3.5 to 10.5 or throughout 49-day storage at 4°C in the absence of glycerol. LH was significantly decreased after freeze-thawing twice, while FSH was resistant to freeze-thaw procedures. CONCLUSIONS: LH and FSH can be determined by ICMA in normal urine pH range (4.6 ~ 8.0). Urine LH is more sensitive to long-term storage and multiple freeze-thaw procedures than FSH.