Free Progesterone

Free Progesterone - Progesterone is a progestin primarily produced through the enzymatic metabolism of pregnenolone. It is enzymatically converted into 17-hydroxy progesterone and 11-deoxycorticosterone. It is secreted by both the gonads and adrenal glands. Most of it binds to cortisol-binding globulin and albumin, with a small portion existing in the "free" form, which is the bioactive component. This "free" progesterone is excreted in the urine mainly as "free" unconjugated progesterone and as pregnanediol.

Progesterone causes cellular changes in the cervix, vagina, and uterus. Levels are lowest during the follicular phase and rise quickly after the luteal surge. Increased progesterone inhibits ovulation. "Free" progesterone significantly increases during pregnancy, reaching about 20% of the total progesterone concentration at delivery. Measuring progesterone can be useful for monitoring fertility, corpus luteum function, endometrial development, and assisting patients undergoing in-vitro fertilization.

Test Details Include:

Free Progesterone %

Free Progesterone (% of Total Progesterone)

Progesterone, Total

Preferred Specimen(s):

3 mL serum

Alternative Specimen(s):

Plasma collected in: EDTA (lavender-top) tube Minimum Volume 2 mL

Methodology:

Radioimmunoassay following ultrafiltration of specimens