Inhibin A (Tumour Marker)

Immunology

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. Total 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 A in women with granulosa cell tumours of the ovary have been shown to exceed those from women with normally functioning ovaries. Serum inhibin A 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 A and B measurement in combination could be used for monitoring all types of ovarian cancer [2].

Indications

Granulosa cell tumours. Can also be used as a marker for Down's screening in the second trimester.

Sample Type

2mL Serum ( Gel 5mL Yellow tube ) or 2mL Plasma ( Li Heparin or EDTA ). Samples may be stored for 24hrs at 2 - 8C or frozen at -20C for a further 30 days. Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

Reference Range

Inhibin A:Female range - post menopausal 0 - 3.6 pg/mL.Values in the premenopausal female vary with the stage of cycle 5 - 160 pg/mL.Male range - 0 - 3.6 pg/mL.Reference ranges established by manufacturer and validated in-house.

Turnaround Time

Within 2 weeks

Testing Frequency

Twice Weekly

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]Aitkin DA, et al. Dimeric inhibin A as a marker for Down's syndrome in early pregnancy. N Eng J Med. 1996. 334:1231-1236. [Ref 3]

Your contact for this test

Clare Del-Duca BSc (Hons) Biomedical Science, MSc Pathological Science

Laboratory Manager - Immunology and Protein Reference Unit

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Inhibin A (Tumour Marker)