Inhibin B

Immunology

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Description

The main application of all tumour markers is monitoring for relapse or progression. Use as a diagnostic aid requires care and knowledge of the test limitations. Opportunistic screening is discouraged. Inhibin is a 32kD glycoprotein secreted by granulosa cells of the ovary and sertoli cells of the testis. It exists as a dimer of two subunits (alpha and beta) linked by disulphide bonds. They selectively suppress the secretion of pituitary follicle stimulating hormone (FSH) and also have local paracrine actions in the gonads [2]. The major clinical use of the inhibin A and B assays are in the diagnosis and treatment monitoring of granulosa and sertoli cell tumours. Levels of inhibin in women with granulosa cell tumours of the ovary have been shown to exceed those from women with normally functioning ovaries. Serum inhibin concentrations in granulosa cell tumours are negatively correlated with FSH levels [1]. The major application is in monitoring patients after surgery for recurrence of the disease. It has been suggested that CA125 and inhibin measurement in combination could be used for monitoring all types of ovarian cancer [2]. Inhibin B is the most common inhibin to be found in males. Prior to puberty inhibin B levels are low, whilst during puberty levels increase [3]. Adults males that have impared spermatogenesis have been shown to have low inhibin B levels alongside elevated FSH. Therefore Inhibin B has been proposed as a marker for male fertility [4].

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Indications

Granulosa cell tumours. Assessment of male and female fertility.

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Sample Type

2mL Serum (Gel 5mL Yellow tube ) or 2mL Heparinised Plasma. Samples should be frozen as soon as possible after separation. Requests from outside Sheffield: Freeze sample prior to dispatch and transport frozen sample at ambient temperature via Royal Mail or Courier (dry ice not required).

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Reference Range

Male (Adult) 24 - 325 pg/mL

Female- post menopausal |0 - 9.8 pg/mL|
Female- pre menopausal* |0 - 341 pg/mL|

*Range in pre-menopausal females vary with the stage of the cycle.

Reference ranges in children vary according to age and sex, see report.
Boys: Age (years)
0-1 |68-630|
1-2 |87-419|
2-6 |42-268|
6-10 |35-167|
10-11 |50-310|
11-12 |104-481|
12-17 |74-470|

Girls:Age (years)
0-1 |<91|
1-3 |<44|
3-6 |<25|
6-9 |<35|
9-11 |<72|
11-16 |<143|
Note: The adult pre-menopausal female range should be used in girls that have started to menstruate.

Reference ranges derived by manufacturer and literature review and validated in-house.

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Turnaround Time

2 Weeks

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Testing Frequency

Within 2 weeks

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References

PRU Handbook of clinical immunochemistry. 9th Edition. 2007. [Ref 1].Robertson DM, et al. Inhibins/activins as diagnostic markers for ovarian cancer. Mol Cell Endocrinol. 2002. 191(1):97-103. [Ref 2].Crofton PM, et al. Inhibin B in boys from birth to adulthood: relationship with age, pubertal stage, FSH and testosterone. Clin Endo. 2002. 56:215-221. [Ref 3].Meachem SJ, Nieschlag E and Simoni M. Inhibin B in male reproduction: pathophysiology and clinical relevance. Euro J Endo. 2001. 145:561-571. [Ref 4].

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See Also

CA125; Inhibin A.

Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.