Thyroid Stimulating Hormone
Get a free nursing lab values cheat sheet at NURSING.com/63labs Objective: Determine the significance and clinical use of Thyroid Stimulating Hormone in clinical practice Lab Test Name: Thyroid Stimulating Hormone Description: Thyroid Stimulating Hormone (TSH) is released from the anterior pituitary in response to low levels of thyroid hormone. TSH stimulates the thyroid gland to release thyroid hormones Triiodothyronine (T3) Thyroxine (T4) T3 and T4 have an inverse relationship with TSH Indications: Aids to diagnose: Hyperthyroidism Hypothyroidism Anterior pituitary function Monitor: Thyroid replacement therapy Normal Therapeutic Values: Normal – 2-10 mU/L Collection: Plasma separator tube What would cause increased levels? TSH levels increase in the following conditions: Hypothyroidism Thyroidectomy Thyroid dysfunction Thyroiditis Thyroid Agenesis Large doses of iodine Pituitary TSH-secreting tumor What would cause decreased levels? Recall the inverse relationship between TSH and T3/T4 labs, and how the negative feedback loop works with these hormones. TSH levels decrease in the following conditions: Anterior pituitary hypofunction- If the pituitary isn’t secreting TSH, the level will be low. Hyperthyroidism- If there is a large amount of thyroid hormone circulating, the feedback system relays the info upstream and less TSH is released.
Thyroid Stimulating Hormone