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Inhibin B

• Introduction
• Indications for Testing
• Detection Method
• Interpretation of Test Results
• Specimen Collection and Shipping Requirements
• Turn around Time
• Cost
• Request Hard Copy
• References

Introduction
Inhibin B serum concentration provides a new measure of ovarian reserve. Ovarian reserve describes the ovary's capacity to respond to gonadotropin stimulation by producing a sufficient number of good quality eggs capable of generating normal embryos.

Granulosa cells of the ovarian follicle secrete Inhibin B. Most of the serum Inhibin B concentration originates from large or dominant follicles since these follicles secrete 10 fold higher concentrations follicles measuring 4 mm. Inhibin B controls FSH secretion form the pituitary gland. Thus, Inhibin B is a more direct measurement of assessing ovarian function than FSH.

Inhibin B serum concentrations drawn on cycle day 3 have been shown to predict response of ovaries to gonadotropin stimulation in invitro fertilization (IVF) cycles. Women who had less than 45 pg/ml Inhibin B on cycle day 3, required 50% more ampules of the day of hCG, 33% reduction in the number of oocytes retrieved, less embryos transferred per cycle and 70% reduction in pregnancy rate, than women with day 3 Inhibin levels greater than 45 pg/ml. The women with day 3 Inhibin levels less than 45 pg/ml that did get pregnant had an 11 fold increase in spontaneous abortions compared with greater than 45 pg/ml.

Indications for Testing
Women aged 35 years or greater, women of any age experiencing unexplained infertility who have a poor response to ovulation induction, women presenting for other tests of ovarian reserve including day 3 FSH and clomiphene challenge test, and women experiencing recurrent pregnancy losses should be tested for day 3 Inhibin B concentrations.

Detection Method
Inhibin B is detected by standard ELISA procedure.

Interpretation of Test Results
The mean value of Inhibin B for normal women on day 3 of the menstrual cycle is 40 pg/ml and the 95% confidence interval of the mean is 33 to 45 pg/ml. Women undergoing IVF with day 3 Inhibin B concentrations less than 45 pg/ml have a pregnancy rate 70% less than women with day 3 Inhibin B concentrations greater that 45 pg/ml.

Specimen Collection and Shipping Requirements

• Collect one (1) 10 ml red or tiger top tube.
• Ship at room temperature in prepaid FedEx mailers overnight, next day morning.

Turn around Time
Processing of specimens begins immediately upon receipt at our facilities. Results are routinely available within 7 to 10 days and are initially faxed, then mailed to the requesting physician.

Cost
Included in our fees are specimen collection and shipping materials, all courier and shipping charges, telephone and written reports, and consultation with physicians. Please call 1-877-737-7652 for pricing information.

Request Hard Copy

References
Mather JP, Moore A, Li RH. Activins, Inhibins and Follistatins: Further thoughts on a growing family of regulators. Pro Doc For Exper Biol & Med 1997;215:209.

Lockwood GM, Muttukrishna S, Groome NP, Knight PG, Ledge WL. Circulating Inhibins and Activin A during GnRH-analogue with recombinant FSH for invitro Fertilization-embryo transfer. Clin Endocrinol 1996;45:741.

Yamoto M, Imai M, Otani H, Nakano R. Serum levels of Inhibin A and Inhibin B in women with normal and abnormal luteal function. Obstet Gynecol 1997;89:773.

Hoffman GE, Danforth DR, Seifer DB. Inhibin B: the physiologic basis of the clomiphene citrate challenge test for ovarian reserve screening. Fertil Steril 1998;69:474.

Seifer DB, Lambert-Messerlian G, Hogan JW, Gardiner AC, Blazar AS, Beck CA. Day 3 serum Inhibin B is predictive of assisted reproductive technologies outcome. Fertil Steril 1997;67:110.

Illingworth PJ, Groome NP, Duncan C, Grant V, Tovanabutra S, Baird DT, McNeilly AS. Measurement of circulating Inhibin forms during the establishment of pregnancy. J Clin Endocrinol & Metabol 1996;81:1471.