Alpha subunit (ASU)
Please note: this test is only requestable by the endocrine consultants.
The measurement of alpha subunit of TSH may be helpful in distinguishing between a TSH-secreting pituitary adenoma and thyroid hormone resistance in patients with a high TSH and FT4. TSH-secreting adenomas are rare and make up 1% of pituitary tumours.
For adults, blood taken into a 6mL red top tube
Do not store. Send at ambient temperature to the laboratory on the day of sample collection.
Relevant clinical details including reason for the request.
Samples are sent for analysis to Queen Elizabeth Hospital, Birmingham with results expected back within 2 weeks.
Adult (male & female) < 1 IU/L
Post-menopausal & mid cycle <3 IU/L
Note: In pregnancy there is 0.1% cross-reactivity with hCG.
To learn more access Supra Regional Assay Service
Page last updated: 12/02/2015