Preferred Sample Type
Suitable Specimen Types
SerumThyrotrophin (TSH)
Specimen Volume
1 ml whole blood minimumSample Preparation
Centrifuge
Turnaround Time
1 daySample Processing In Laboratory
Usual
Sample Stability
Store at between 2-8°C for up to 7 days.
Store separated serum/plasma frozen if analysis is to be delayed.
General Information
The synthesis and secretion of TSH is stimulated by Thyrotrophin Releasing Hormone (TRH) in response to low levels of circulating thyroid hormones. TSH is formed in specific basophil cells of the anterior pituitary gland and is subject to a circadian secretion sequence. TSH has a stimulating action in all stages of thyroid hormone formation and secretion from the Thyroid gland. Determination of TSH serves as an initial test of thyroid function as levels will change in response to small changes in the concentrations of circulating free thyroid hormone levels.
Patient Preparation
Patients receiving therapy with biotin (> 5mg/day) should not have samples taken for analysis until at least 8 hours post dose.
Notes
TSH is measured as part of a TFT including fT4. Patients receiving therapy with biotin (> 5mg/day) should not have samples taken for analysis until at least 8 hours post dose. In rare cases, interference due to extremely high titers of antibodies to analyte or to analyte‑specific antibodies, streptavidin or ruthenium can occur. Please contact the laboratory for further advice if tests results are not consistent with the patient's medical history, clinical presentation and/or other findings, as further interference studies can be performed.
Reference Range
Adult reference range = 0.40-4.90 mIU/L
Source of Reference Range
Abbott DiagnosticsSpecifications
- EQA Status: NEQAS
- EQAS Scheme: Yes