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Paediatric Laboratory Medicine

TSH, Blood

Clinical Significance

Human Thyroid Stimulating Hormone (TSH) or thyrotropin is a glycoprotein with a molecular weight of approximately 28,000 daltons, synthesized by the basophilic cells (thyrotropes) of the anterior pituitary. TSH stimulates the production and secretion of the metabolically active thyroid hormones, thyroxine (T4) and triiodothyronine (T3), by interacting with a specific receptor on the thyroid cell surface. T3 and T4 are responsible for regulating diverse biochemical processes throughout the body which are essential for normal development and metabolic and neural activity. Failure at any level of regulation of the hypothalamic-pituitary-thyroid axis will result in either underproduction (hypothyroidism) or overproduction (hyperthyroidism) of T4 and/or T3. Primary hyperthyroidism (e.g., Grave’s Disease, nodular goiter) is associated with high levels of thyroid hormones and depressed or undetectable levels of TSH.

Test Name

TSH, Blood

Test Code



Biochemistry - Biochemistry


Abbott Ci4100

External Proficiency Testing


Turn Around Time

Monday to Friday

Specimen Type

Serum, Sodium/Lithium Heparin / K EDTA plasma

Minimum Specimen Requirements

300 uL



Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Reference Range

< 5 days : 3.2-19 mIU/L
6 - 30 days : 1.7-9.1 mIU/L
1- 2 months : 0.5-6.3 mIU/L
3 - <6 months : 0.5-4.77 mIU/L
6 months - < 1 year : 0.61-4.58 mIU/L
1 - <14 years : 0.73-4.09 mIU/L
14- <19 years : 0.47-4.00 mIU/L