ALPHA SUBUNIT - serum

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Specimen: 5 mL blood in plain tube.

Method: Immunoassay.

Reference Interval:

Male:	<0.6 IU/L
Female:	<1.0 IU/L (premenopausal)
	<2.0 IU/L (postmenopausal)
	Levels in pregnancy may be >2.0 IU/L

Application: Detection of endocrine tumours secreting only the free a chains of the glycoprotein hormones (LH, FSH, hCG, TSH).

Interpretation: Some pituitary tumours secrete little or no intact hormone, but produce the common a subunit of glycoprotein hormones, at times in massive amounts.

Reference: Snyder PJ. Endocrine Reviews 1985; 6: 552-563. Molitch ME. N Engl J Med 1991; 324: 626-627.

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