Glycerol prevents loss of immunoreactive follicle-stimulating hormone and luteinizing hormone from frozen urine.

First morning urine samples were collected from both menstruant and post-menopausal women and stored at -25 degrees C. Immunoreactive FSH disappeared from these samples (t1/2 = 30 days), ultimately stabilizing at about 20% of the initial value. The loss was more rapid at -20 degrees C and less rapid at -55 degrees C and +4 degrees C. Immunoreactive LH was also lost from frozen urine, but more slowly than FSH. The addition of glycerol to urine (0.52 mol/l) stored at -25 degrees C prevented loss of immunoreactive FSH and LH for at least 105 days.