Tests for pituitary hormone excess or deficiency - McMaster Textbook of Internal Medicine

Table 6.3-3. Tests for pituitary hormone excess or deficiency
Cause	Test of choice
Pituitary hormone overproduction (usually if clinically suspected)
Prolactinoma	Serum prolactin measurement (in all)
Cushing syndrome	1-mg dexamethasone suppression test or late-night salivary cortisol test, or 24-h urinary free cortisol test
Acromegaly	Serum IGF-1 level
Thyrotropinoma	FT4, FT3, TSH
Pituitary hormone deficiency
Adrenal insufficiency	Early morning serum cortisol with ACTH measurement ± ACTH stimulation test
Hypothyroidism	Serum TSH and FT4 measurement (FT4 measurement is the best test for central hypothyroidism)
Hypogonadism	Men: Early morning testosterone measurement with LH measurement Women: Presence of menstrual periods in premenopausal women. In case of oligomenorrhea or amenorrhea: estradiol and FSH measurement
Central diabetes insipidus/vasopressin deficiency	Serum sodium measurement, serum and urine osmolality, water deprivation test if needed (in masses >1 cm and if symptoms are present)
ACTH, adrenocorticotropic hormone; FSH, follicle-stimulating hormone; FT3, free triiodothyronine; FT4, free thyroxine; IGF-1, insulin-like growth factor 1; TSH, thyroid-stimulating hormone.