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PTD - 341

Test Directory -  Inhibin B

Clinical Indications

Inhibin B has been used as a marker of ovarian reserve. Every female is born with a specific number of follicles containing oocytes, a number that steadily and naturally declines with age. The number of follicles remaining in the ovary at any time is called the ovarian reserve. As ovarian reserve diminishes, it is increasingly more difficult for the hormones used for in vitro fertilization (IVF) to stimulate follicle development and, thus, the likelihood of successful oocyte retrieval, fertilization, and embryo transfer decreases, all leading to a lower chance of conceiving. As part of an infertility evaluation, attempts are made to estimate a woman’s ovarian reserve. Tests to assess ovarian reserve include: day 3 FSH, day 3 inhibin B, and antimullerian hormone levels. The amount of inhibin B measured in serum during the early follicular phase of the menstrual cycle (day 3) directly reflects the number of follicles in the ovary.

Inhibin B concentrations are elevated in patients with granulosa cell tumours, over 80% of those with mucinous cystadenocarcinoma and in about 20% of  those with other ovarian tumours. They can also be elevated in ovarian benign pathology.

Request Form

Combined Pathology Blood form (Yellow/Black)

Availability

Analysed by Protein Reference Unit, Sheffield, if specific criteria met.

Specific Criteria

May be used for infertility evaluation. May be also used for monitoring recurrence of granulosa cell tumours.

Patient Preparation

None

Limitations

 

Sample must be transported to laboratory and separated within 30 minutes of collection. Patients must be bled at Basildon Hospital.

Turnaround Time

3 weeks

Specimen

Serum

Volume

2 ml

Container

Yellow top (SST) tube

Causes for Rejection

Not meeting specific criteria for analysis. Delay in sample reaching laboratory. 

Reference Ranges

Female range- post menopausal 0 - 4 pg/mL. Values in the pre menopausal female vary with the stage of the cycle 0 - 341 pg/mL. Male range 25 - 325 pg/mL. Reference ranges in children vary according to age and sex,

Reference: Referral laboratory

Interpretation

Inhibin levels vary in relation to the menstrual cycle and, therefore, are difficult to interpret in premenopausal women when used as an ovarian cancer marker.

Lab. Handling

Processing: Centrifuge and aliquot immediately into 2 aliquots and freeze at -20°C in the separating freezer (CB40), active frozen rack 110.
Referral: SASOD and send or BPRO and save in separating freezer (CB40), at -20°C in the saved frozen rack.

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Version 1.0 / April 2015                                                                                                          Approved by: Consultant Biochemist