Free Progesterone, Urine

Clinical Significance:
Progesterone is a Progestin produced primarily from enzymatic metabolism of Pregnenolone.  It is enzymatically converted to 17-Hydroxy Progestrone and 11-Deoxycorticosterone.  It is secreted by both the gonads and the adrenal glands.  It is bound to Cortisol Binding Globulin and Albumin, but a small percentage is present in the “Free” bioactive form.  It is excreted into the urine as its conjugated and “Free” unconjugated forms and as Pregnanediol (conjugated and unconjugated).  This assay measures only the “Free” unconjugated form of Progesterone. Urinary “Free” Progesterone levels parallel blood levels offering a non-invasive method of specimen collection. Progesterone is responsible for cellular changes in the cervix, vagina, and uterus.  Levels are lowest in the follicular phase and increase rapidly following the luteal surge.  Progesterone increases greatly during pregnancy.  Measurement of Urinary “Free” Progesterone can be useful to monitor fertility, corpus luteum function, endometrial development, and be helpful in in-vitro fertilization patients yielding an integrated look of Progesterone activity over a 24 hour period.

Reference Ranges:
Male:                      Up to 0.2 ug/24 hours
  Follicular:              Up to 0.2 ug/24 hours
  Luteal:                   0.4 –  2.5 ug/24 hours

Urinary “Free” Progesterone is measured by radioimmunoassay following extraction of specimens.

Patient Preparation:
Patient should not be on any Corticosteroid, ACTH, Estrogen, or Gonadotropin medication, if possible, for at least 48 hours prior to collection of specimen.

Specimen Collection:
10 ml of a 24 hour urine collection should be submitted for analysis. No special preservatives are required. Store specimen refrigerated during collection. Specimens should be frozen prior to shipping. Minimum specimen size is 5 ml.

Shipping Instructions:
Ship specimens frozen in dry ice. Provide the total volume per 24 hours.

2. HJ van der Molem and C Corpechot.  Isolation and Identification of Progesterone from Urine of Nonpregnant Women.  Journal of Clinical Endocrinology and Metabolism  28: 1361, 1968.

2. CJ Munro, GH Stabenfeldt, JR Cragun, LA Addiego, JW Overstreet, and BL Lasley.  Relationship of Serum Estradiol and Progesterone Concentrations to the Excretion Profiles of Their Major Urinary Metabolites as Measured by Enzyme Immunoassay and Radioimmunoassay.  Clinical Chemistry 37: 38-44, 1991.